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.

A060553 a(n) is the number of distinct (modulo geometric D3-operations) patterns which can 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 2
2 2
3 4
4 6
5 10
6 16
7 32
8 52
9 104
10 192
11 376
12 720
13 1440
14 2800
15 5600
16 11072
17 22112
18 43968
19 87936
20 175296
21 350592
22 700160
23 1400192
24 2798336
25 5596672
26 11188992
27 22377984
28 44747776
29 89495040
30 178973696
31 357947392
32 715860992
33 1431721984
34 2863378432
35 5726754816

List of values

[2, 2, 4, 6, 10, 16, 32, 52, 104, 192, 376, 720, 1440, 2800, 5600, 11072, 22112, 43968, 87936, 175296, 350592, 700160, 1400192, 2798336, 5596672, 11188992, 22377984, 44747776, 89495040, 178973696, 357947392, 715860992, 1431721984, 2863378432, 5726754816]

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement.