A093985 - cp's OEIS frontend

A093985 a(1) = 1, a(2) = 2; a(n+1) = 2n*a(n) - a(n-1). Symmetrically, a(n) = (a(n-1) + a(n+1))/((n-1) + (n+1)).

n	a(n)
1	1
2	2
3	7
4	40
5	313
6	3090
7	36767
8	511648
9	8149601
10	146181170
11	2915473799
12	63994242408
13	1532946343993
14	39792610701410
15	1112660153295487
16	33340011988163200
17	1065767723467926913
18	36202762585921351842
19	1302233685369700739399
20	49448677281462706745320

[1, 2, 7, 40, 313, 3090, 36767, 511648, 8149601, 146181170, 2915473799, 63994242408, 1532946343993, 39792610701410, 1112660153295487, 33340011988163200, 1065767723467926913, 36202762585921351842, 1302233685369700739399, 49448677281462706745320]

cp's OEIS Frontend

A093985 a(1) = 1, a(2) = 2; a(n+1) = 2n*a(n) - a(n-1). Symmetrically, a(n) = (a(n-1) + a(n+1))/((n-1) + (n+1)).

Table of values

List of values