A134999 - OEIS

A134999

Triangle-shaped numbers.

100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 148, 149, 150, 151

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

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, ...

LINKS

Table of n, a(n) for n=1..48.

EXAMPLE

The triangle number 1024:

. . . 4

. . . .

. . 2 .

1 . . .

. 0 . .

CROSSREFS

Cf. A134810, A135600, A135601, A135602, A135603, A135643.

Not to be confused with the triangular numbers, A000217!