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Gematria · Latin script · cipher 11 of 23

Trigonal: each letter's triangular number

The Trigonal cipher is the one that gives each letter the triangular number of its place in the alphabet, the sum of all the numbers up to it: A 1, B 3, C 6, D 10, up to Z 351. The arithmetic is ancient; the cipher is a website coinage of the 2010s.

A table of the 26 Latin letters, each with its value under Trigonal: A 1, B 3, C 6, D 10, E 15, F 21, G 28, H 36, I 45, J 55, K 66, L 78, M 91, N 105, O 120, P 136, Q 153, R 171, S 190, T 210, U 231, V 253, W 276, X 300, Y 325, Z 351. Trigonal A 1 B 3 C 6 D 10 E 15 F 21 G 28 H 36 I 45 J 55 K 66 L 78 M 91 N 105 O 120 P 136 Q 153 R 171 S 190 T 210 U 231 V 253 W 276 X 300 Y 325 Z 351
The Trigonal letter table as the chart uses it: every letter of the alphabet with its value. Letters are counted in this order, A to Z.

Facts

Script
The 26 Latin letters; accents stripped, Ø, Æ and ß folded to O, AE and SS
Rule
The nth letter is 1 + 2 + … + n: A 1, B 3, C 6 … Z 351
Tier in our chart
More: behind "more ciphers"
Built from
The English Ordinal: n(n + 1) ÷ 2 for the nth letter
First known source
Gematrinator's cipher list; 2010s
Its link to Offset 36
666 is the 36th triangular number
Example
GEMATRIA = 562; ALPHABET = 480

Meaning

A triangular number counts the dots in a triangle: one dot, then a row of two below it, then three, and so on. The nth triangular number is 1 + 2 + … + n. The Trigonal cipher gives each letter the triangular number of its place: A is 1, B 3, C 6, D 10, and Z, the 26th letter, 351. Values grow fast, so the later letters dominate a total much as they do in Agrippa's table, but smoothly rather than in jumps.

Figurate numbers of this kind were studied in Greek arithmetic, and the Pythagoreans are credited with them in later tradition. The cipher is something else: a way of valuing the English alphabet listed on Gematrinator in the 2010s, with no older source. One triangular number explains another of the community's ciphers: 1 + 2 + … + 36 is 666, which is why the cipher we call Offset 36 begins at 36.

How it is counted

GEMATRIA: G 28 + E 15 + M 91 + A 1 + T 210 + R 171 + I 45 + A 1 = 562; reduced to 13, then to 4. ALPHABET: A 1 + L 78 + P 136 + H 36 + A 1 + B 3 + E 15 + T 210 = 480; reduced to 12, then to 3.

Each value can be checked by the formula n(n + 1) ÷ 2: R, the 18th letter, is 18 × 19 ÷ 2 = 171.

What this page leaves out

The reverse form of this cipher, which our old chart showed, was dropped in October 2026 with the other mirrors. We give no reading of a Trigonal total.

How it relates to the other ciphers

Since the nth triangular number is half of n squared plus n, a word's Trigonal total is half the sum of its Squares and English Ordinal totals. GEMATRIA gives 1,050 and 74, whose sum halved is 562; ALPHABET gives 895 and 65, halved 480. The three ciphers are one piece of arithmetic seen three ways, and a match under one of them is often a match under the others for the same reason.

Correspondences

Each item with how it stands: “sourced” is in the work cited, “our construction” is EsoTerrier’s own, and “disputed” means the sources disagree.

Name on the popular sites
"Trigonal" (Gematrinator) sourced
Triangular numbers
The figurate numbers of Greek arithmetic, dots set out in triangles sourced
Tradition
None for the cipher; triangular numbers are old, applying them to English letters is not sourced

How the schools read it

Gematrinator
Lists it, with a reverse form we do not compute.
EsoTerrier
Behind "more ciphers", labelled as a modern cipher.

Claims about it

  • The Trigonal cipher is Pythagorean, because triangular numbers are.

    false

    What the record shows: Triangular numbers belong to Greek arithmetic; this cipher, which applies them to the English alphabet, appears on the gematria sites of the 2010s.

  • Two words or names with the same value under this cipher are connected.

    false

    What the record shows: Equal values are what any table of this kind produces in quantity; the tradition reads them together as a way of interpreting a text.

  • Totals under this cipher show that news events are planned by their numbers.

    false

    What the record shows: A search with dozens of ciphers and millions of phrases always finds a match; fact-checkers have shown it. Nothing on this site reads events, dates or news by number.

Elsewhere on EsoTerrier

Sources

Primary texts (1)
  1. Gematrinator (Derek Tikkuri), ciphers and FAQ. Facts only. gematrinator.com/ciphers
Studies and other sources (2)
  1. Carl Huffman, "Pythagoras", Stanford Encyclopedia of Philosophy (2024). plato.stanford.edu/entries/pythagoras
  2. Lead Stories, "Fact check: gematria codes used by conspiracy theories always result in matches" (2022). leadstories.com/hoax-alert/2022/01/fact-check-gematria-codes-used-by-conspiracy-theories-always-result-in-matches.html
Our own research (3)
  1. EsoTerrier calculation engine, the gematria service and its documentation.
  2. EsoTerrier, numerology, Psychomatrix and gematria research, 10 to 13 October 2026: the cipher table and its keep, add and drop decisions.
  3. EsoTerrier, example values of test words under every cipher, computed from the engine's tables (October 2026).

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By EsoTerrier. Written with AI assistance from our research and checked against its sources; last revised 20 October 2026. How we write these pages.

First published ; last revised . Corrections: support@esoterrier.com.