A221987 - cp's OEIS frontend

A221987 G.f.: A(x,y) = Sum_{n>=0} n!x^ny^n * Product_{k=1..n} (1+y + 2kxy) / (1 + (1+y)kx + 2k^2x^2y).

n	a(n)
0	1
1	1
2	1
3	1
4	4
5	1
6	1
7	11
8	11
9	1
10	1
11	26
12	62
13	26
14	1
15	1
16	57
17	274
18	274
19	57
20	1
21	1
22	120
23	1063
24	2024
25	1063
26	120
27	1
28	1
29	247
30	3805
31	12411
32	12411
33	3805
34	247
35	1
36	1
37	502
38	12916
39	67882
40	113414
41	67882
42	12916
43	502
44	1
45	1
46	1013
47	42284
48	343700
49	891930
50	891930
51	343700
52	42284
53	1013
54	1

[1, 1, 1, 1, 4, 1, 1, 11, 11, 1, 1, 26, 62, 26, 1, 1, 57, 274, 274, 57, 1, 1, 120, 1063, 2024, 1063, 120, 1, 1, 247, 3805, 12411, 12411, 3805, 247, 1, 1, 502, 12916, 67882, 113414, 67882, 12916, 502, 1, 1, 1013, 42284, 343700, 891930, 891930, 343700, 42284, 1013, 1]

cp's OEIS Frontend

A221987 G.f.: A(x,y) = Sum_{n>=0} n!x^ny^n * Product_{k=1..n} (1+y + 2kxy) / (1 + (1+y)kx + 2k^2x^2y).

Table of values

List of values

cp's OEIS Frontend

A221987 G.f.: A(x,y) = Sum_{n>=0} n!*x^n*y^n * Product_{k=1..n} (1+y + 2*k*x*y) / (1 + (1+y)*k*x + 2*k^2*x^2*y).

Table of values

List of values

A221987 G.f.: A(x,y) = Sum_{n>=0} n!x^ny^n * Product_{k=1..n} (1+y + 2kxy) / (1 + (1+y)kx + 2k^2x^2y).