cp's OEIS Frontend

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.

A060551 a(n) is the number of nonsymmetric patterns (no reflective, nor rotational symmetry) which may be formed by an equilateral triangular arrangement of closely packed black and white cells satisfying the local matching rule of Pascal's triangle modulo 2, where n is the number of cells in each edge of the arrangement. The matching rule is such that any elementary top-down triangle of three neighboring cells in the arrangement contains either one or three white cells.

Table of values

n a(n)
1 0
2 0
3 0
4 6
5 12
6 42
7 84
8 210
9 420
10 924
11 1860
12 3900
13 7800
14 15996
15 31992
16 64728
17 129528
18 260568
19 521136
20 1045464
21 2090928
22 4187952
23 8376240
24 16764720
25 33529440
26 67084080
27 134168160
28 268385376
29 536772192
30 1073642592
31 2147285184
32 4294769760
33 8589539520
34 17179472064

List of values

[0, 0, 0, 6, 12, 42, 84, 210, 420, 924, 1860, 3900, 7800, 15996, 31992, 64728, 129528, 260568, 521136, 1045464, 2090928, 4187952, 8376240, 16764720, 33529440, 67084080, 134168160, 268385376, 536772192, 1073642592, 2147285184, 4294769760, 8589539520, 17179472064]