A294811 - cp's OEIS frontend

A294811 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 triangular numbers (A000217). Then a(n) = b(n)/A010551(n).

n	a(n)
0	1
1	1
2	1
3	1
4	2
5	4
6	6
7	11
8	16
9	30
10	48
11	97
12	157
13	322
14	524
15	1077
16	1777
17	3684
18	6157
19	12876
20	21684
21	45520
22	77212
23	162533
24	277608
25	585993
26	1006784
27	2129433
28	3677453
29	7788711
30	13514487
31	28654668
32	49933938
33	105964856
34	185377690
35	393631445
36	691101516
37	1468137470

[1, 1, 1, 1, 2, 4, 6, 11, 16, 30, 48, 97, 157, 322, 524, 1077, 1777, 3684, 6157, 12876, 21684, 45520, 77212, 162533, 277608, 585993, 1006784, 2129433, 3677453, 7788711, 13514487, 28654668, 49933938, 105964856, 185377690, 393631445, 691101516, 1468137470]

cp's OEIS Frontend

A294811 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 triangular numbers (A000217). Then a(n) = b(n)/A010551(n).

Table of values

List of values