A121690 - cp's OEIS frontend

A121690 G.f.: A(x) = Sum_{k>=0} x^k * (1+x)^(k*(k+1)/2).

n	a(n)
0	1
1	1
2	2
3	4
4	10
5	27
6	81
7	262
8	910
9	3363
10	13150
11	54135
12	233671
13	1053911
14	4951997
15	24177536
16	122381035
17	640937746
18	3466900453
19	19337255086
20	111057640382
21	655892813805
22	3978591077096
23	24760700544301
24	157941950878839

[1, 1, 2, 4, 10, 27, 81, 262, 910, 3363, 13150, 54135, 233671, 1053911, 4951997, 24177536, 122381035, 640937746, 3466900453, 19337255086, 111057640382, 655892813805, 3978591077096, 24760700544301, 157941950878839]

cp's OEIS Frontend

A121690 G.f.: A(x) = Sum_{k>=0} x^k * (1+x)^(k*(k+1)/2).

Table of values

List of values