This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A134999 #7 Aug 03 2022 02:33:51 %S A134999 100,101,102,103,104,105,106,107,108,109,110,112,113,114,115,116,117, %T A134999 118,119,120,121,122,124,125,126,127,128,129,130,131,132,133,134,136, %U A134999 137,138,139,140,141,142,143,144,145,146,148,149,150,151 %N A134999 Triangle-shaped numbers. %C A134999 The structure of digits represents a triangle. Three digits are the vertex. In the graphic representation the points are connected by imaginary line segments. All 3-digit numbers are terms of this sequence, except for the straight-line numbers A135643. For 4 or more digits the terms are 1000, 1011, 1012, 1024, 1034, 1036, ... %e A134999 The triangle number 1024: %e A134999 . . . 4 %e A134999 . . . . %e A134999 . . 2 . %e A134999 1 . . . %e A134999 . 0 . . %Y A134999 Cf. A134810, A135600, A135601, A135602, A135603, A135643. %Y A134999 Not to be confused with the triangular numbers, A000217! %K A134999 base,nonn %O A134999 1,1 %A A134999 _Omar E. Pol_, Dec 05 2007