A294812 - cp's OEIS frontend

A294812 Let b(n) be the number of permutations {c_1..c_n} of {1..n} for which c_1 - c_2 + ... + (-1)^(n-1)*c_n are pentagonal numbers (A000326). Then a(n) = b(n)/A010551(n).

n	a(n)
1	1
2	1
3	1
4	2
5	4
6	5
7	6
8	10
9	23
10	38
11	70
12	110
13	196
14	346
15	759
16	1250
17	2313
18	3982
19	8433
20	14520
21	29437
22	50466
23	102830
24	179587
25	376439
26	654374
27	1343540
28	2352149
29	4916286
30	8654120
31	18065200
32	31783592
33	66233160
34	117371504
35	246610521
36	436972949
37	913862320
38	1626523783

[1, 1, 1, 2, 4, 5, 6, 10, 23, 38, 70, 110, 196, 346, 759, 1250, 2313, 3982, 8433, 14520, 29437, 50466, 102830, 179587, 376439, 654374, 1343540, 2352149, 4916286, 8654120, 18065200, 31783592, 66233160, 117371504, 246610521, 436972949, 913862320, 1626523783]

cp's OEIS Frontend

A294812 Let b(n) be the number of permutations {c_1..c_n} of {1..n} for which c_1 - c_2 + ... + (-1)^(n-1)*c_n are pentagonal numbers (A000326). Then a(n) = b(n)/A010551(n).

Table of values

List of values