A210685 - cp's OEIS frontend

A210685 a(1)=-1, a(2)=2, thereafter a(n) = (1/(2n))*((7n-22)a(n-1)+2(2n-1)a(n-2)).

n	a(n)
1	-1
2	2
3	-2
4	2
5	-1
6	2
7	2
8	8
9	22
10	68
11	212
12	678
13	2207
14	7298
15	24458
16	82928
17	284066
18	981884
19	3421316
20	12007556
21	42416486
22	150718772
23	538421588
24	1932856592
25	6969847484
26	25237057112
27	91729488352
28	334589415278
29	1224445617887
30	4494622119426
31	16545704494682
32	61071167108960
33	225982053183050

[-1, 2, -2, 2, -1, 2, 2, 8, 22, 68, 212, 678, 2207, 7298, 24458, 82928, 284066, 981884, 3421316, 12007556, 42416486, 150718772, 538421588, 1932856592, 6969847484, 25237057112, 91729488352, 334589415278, 1224445617887, 4494622119426, 16545704494682, 61071167108960, 225982053183050]

cp's OEIS Frontend

A210685 a(1)=-1, a(2)=2, thereafter a(n) = (1/(2n))*((7n-22)a(n-1)+2(2n-1)a(n-2)).

Table of values

List of values