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.

A243208 Number of inequivalent (mod D_3) ways to place 3 points on a triangular grid of side n so that they are not vertices of an equilateral triangle with sides parallel to the grid.

Table of values

n a(n)
2 0
3 3
4 20
5 77
6 223
7 552
8 1196
9 2380
10 4388
11 7657
12 12710
13 20301
14 31297
15 46892
16 68426
17 97674
18 136596
19 187713
20 253770
21 338217
22 444773
23 578018
24 742852
25 945210
26 1191398
27 1488949
28 1845824
29 2271415
30 2775605
31 3369930
32 4066480
33 4879238
34 5822810
35 6913947
36 8170098
37 9611127
38 11257671

List of values

[0, 3, 20, 77, 223, 552, 1196, 2380, 4388, 7657, 12710, 20301, 31297, 46892, 68426, 97674, 136596, 187713, 253770, 338217, 444773, 578018, 742852, 945210, 1191398, 1488949, 1845824, 2271415, 2775605, 3369930, 4066480, 4879238, 5822810, 6913947, 8170098, 9611127, 11257671]

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

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