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.

A359689 a(n) is the number of free polyiamonds of n cells with chessboard coloring.

Table of values

n a(n)
1 2
2 1
3 2
4 4
5 8
6 19
7 48
8 120
9 320
10 864
11 2372
12 6581
13 18470
14 52094
15 147966
16 421931
17 1208214
18 3470789
19 10001186
20 28892674
21 83671476
22 242823392
23 706090582
24 2056861981
25 6001601254
26 17538308071
27 51323923796
28 150389970179
29 441211039118
30 1295886198194
31 3810209524640
32 11214075937205
33 33035791339150

List of values

[2, 1, 2, 4, 8, 19, 48, 120, 320, 864, 2372, 6581, 18470, 52094, 147966, 421931, 1208214, 3470789, 10001186, 28892674, 83671476, 242823392, 706090582, 2056861981, 6001601254, 17538308071, 51323923796, 150389970179, 441211039118, 1295886198194, 3810209524640, 11214075937205, 33035791339150]