A006720 - cp's OEIS frontend

A006720 Somos-4 sequence: a(0)=a(1)=a(2)=a(3)=1; for n >= 4, a(n) = (a(n-1) * a(n-3) + a(n-2)^2) / a(n-4).

n	a(n)
0	1
1	1
2	1
3	1
4	2
5	3
6	7
7	23
8	59
9	314
10	1529
11	8209
12	83313
13	620297
14	7869898
15	126742987
16	1687054711
17	47301104551
18	1123424582771
19	32606721084786
20	1662315215971057
21	61958046554226593
22	4257998884448335457
23	334806306946199122193
24	23385756731869683322514
25	3416372868727801226636179

[1, 1, 1, 1, 2, 3, 7, 23, 59, 314, 1529, 8209, 83313, 620297, 7869898, 126742987, 1687054711, 47301104551, 1123424582771, 32606721084786, 1662315215971057, 61958046554226593, 4257998884448335457, 334806306946199122193, 23385756731869683322514, 3416372868727801226636179]

cp's OEIS Frontend

A006720 Somos-4 sequence: a(0)=a(1)=a(2)=a(3)=1; for n >= 4, a(n) = (a(n-1) * a(n-3) + a(n-2)^2) / a(n-4).

Table of values

List of values