A015506 - cp's OEIS frontend

A015506 a(1) = 1, a(n) = Sum_{k=1}^{n-1} (5^k - 1)/4 a(k).

n	a(n)
1	1
2	1
3	7
4	224
5	35168
6	27501376
7	107447876032
8	2098671914657024
9	204950003169660992768
10	100073397447688408870744576
11	244319893042568615235897903058432
12	2982420752607212448380293251367177293824

[1, 1, 7, 224, 35168, 27501376, 107447876032, 2098671914657024, 204950003169660992768, 100073397447688408870744576, 244319893042568615235897903058432, 2982420752607212448380293251367177293824]

cp's OEIS Frontend

A015506 a(1) = 1, a(n) = Sum_{k=1}^{n-1} (5^k - 1)/4 a(k).

Table of values

List of values