A015507 - cp's OEIS frontend

A015507 a(1) = 1, a(n) = Sum_{k=1..n-1} ((6^k - 1)/5)*a(k).

n	a(n)
1	1
2	1
3	8
4	352
5	91520
6	142405120
7	1328924579840
8	74403829376081920
9	24994031979330942894080
10	50376471215620688640734003200
11	609214555257707874214915513922355200
12	44204249911340791820804231319883906967142400

[1, 1, 8, 352, 91520, 142405120, 1328924579840, 74403829376081920, 24994031979330942894080, 50376471215620688640734003200, 609214555257707874214915513922355200, 44204249911340791820804231319883906967142400]

cp's OEIS Frontend

A015507 a(1) = 1, a(n) = Sum_{k=1..n-1} ((6^k - 1)/5)*a(k).

Table of values

List of values