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.

A239569 Number of ways to place 3 points on a triangular grid of side n so that no two of them are adjacent.

Table of values

n a(n)
2 0
3 1
4 21
5 151
6 615
7 1845
8 4571
9 9926
10 19566
11 35805
12 61765
13 101541
14 160381
15 244881
16 363195
17 525260
18 743036
19 1030761
20 1405221
21 1886035
22 2495955
23 3261181
24 4211691
25 5381586
26 6809450
27 8538725
28 10618101
29 13101921
30 16050601
31 19531065
32 23617195
33 28390296
34 33939576

List of values

[0, 1, 21, 151, 615, 1845, 4571, 9926, 19566, 35805, 61765, 101541, 160381, 244881, 363195, 525260, 743036, 1030761, 1405221, 1886035, 2495955, 3261181, 4211691, 5381586, 6809450, 8538725, 10618101, 13101921, 16050601, 19531065, 23617195, 28390296, 33939576]