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.

A387511 a(n) = Sum_{k=0..floor(n/3)} 3^k * 2^(n-2*k) * binomial(n-2*k,k)^2.

Table of values

n a(n)
0 1
1 2
2 4
3 14
4 64
5 248
6 868
7 3176
8 12352
9 48344
10 186688
11 720896
12 2810128
13 11021984
14 43290688
15 170193632
16 670576384
17 2648370560
18 10477291072
19 41502538880
20 164602863616
21 653632824704
22 2598446927872
23 10339935936512
24 41181966803200
25 164155849556480
26 654848284582912

List of values

[1, 2, 4, 14, 64, 248, 868, 3176, 12352, 48344, 186688, 720896, 2810128, 11021984, 43290688, 170193632, 670576384, 2648370560, 10477291072, 41502538880, 164602863616, 653632824704, 2598446927872, 10339935936512, 41181966803200, 164155849556480, 654848284582912]