A337555 - cp's OEIS frontend

A337555 a(0) = 1; a(n) = (1/2) * Sum_{k=1..n} binomial(n,k) * (3^k-1) * a(n-k).

n	a(n)
0	1
1	1
2	6
3	43
4	408
5	4861
6	69516
7	1159663
8	22108848
9	474192601
10	11300589876
11	296237533483
12	8471642214888
13	262456441714741
14	8756520140416236
15	313017838828154503
16	11935355244756882528
17	483537933291091103281
18	20741938090482567562596
19	939180816648348685174723

[1, 1, 6, 43, 408, 4861, 69516, 1159663, 22108848, 474192601, 11300589876, 296237533483, 8471642214888, 262456441714741, 8756520140416236, 313017838828154503, 11935355244756882528, 483537933291091103281, 20741938090482567562596, 939180816648348685174723]

cp's OEIS Frontend

A337555 a(0) = 1; a(n) = (1/2) * Sum_{k=1..n} binomial(n,k) * (3^k-1) * a(n-k).

Table of values

List of values