A364525 - cp's OEIS frontend

A364525 a(n) is the number of distinct ways to partition the set {1,2,...,n} into nonempty subsets such that the sum of the pi(x)*(pi(x) + 1)/2 values of each subset's size x equals n, where pi() is the prime counting function given by A000720.

n	a(n)
1	0
2	0
3	1
4	1
5	2
6	5
7	9
8	18
9	36
10	73
11	145
12	290
13	580
14	1159
15	2319
16	4637
17	9273
18	18544
19	37083
20	74157
21	148330
22	296658
23	593311
24	1186613
25	2373208
26	4746380
27	9492687
28	18985447
29	37970821
30	75941497
31	151882704
32	303764828
33	607528497
34	1215054675
35	2430104713
36	4860217541

[0, 0, 1, 1, 2, 5, 9, 18, 36, 73, 145, 290, 580, 1159, 2319, 4637, 9273, 18544, 37083, 74157, 148330, 296658, 593311, 1186613, 2373208, 4746380, 9492687, 18985447, 37970821, 75941497, 151882704, 303764828, 607528497, 1215054675, 2430104713, 4860217541]

cp's OEIS Frontend

A364525 a(n) is the number of distinct ways to partition the set {1,2,...,n} into nonempty subsets such that the sum of the pi(x)*(pi(x) + 1)/2 values of each subset's size x equals n, where pi() is the prime counting function given by A000720.

Table of values

List of values