A307242 - cp's OEIS frontend

A307242 a(0) = 1; a(n) = Sum_{k=1..n} (-1)^(k+1)sigma_2(k+1)a(n-k), where sigma_2() is the sum of squares of divisors (A001157).

n	a(n)
0	1
1	5
2	15
3	46
4	159
5	570
6	2036
7	7208
8	25400
9	89456
10	315335
11	1112286
12	3923867
13	13841052
14	48818892
15	172186234
16	607314043
17	2142064478
18	7555322206
19	26648517536
20	93992371863
21	331521717928
22	1169314641890
23	4124305724658
24	14546896171716
25	51308559972146
26	180971133233105
27	638305788168090

[1, 5, 15, 46, 159, 570, 2036, 7208, 25400, 89456, 315335, 1112286, 3923867, 13841052, 48818892, 172186234, 607314043, 2142064478, 7555322206, 26648517536, 93992371863, 331521717928, 1169314641890, 4124305724658, 14546896171716, 51308559972146, 180971133233105, 638305788168090]

cp's OEIS Frontend

A307242 a(0) = 1; a(n) = Sum_{k=1..n} (-1)^(k+1)sigma_2(k+1)a(n-k), where sigma_2() is the sum of squares of divisors (A001157).

Table of values

List of values

cp's OEIS Frontend

A307242 a(0) = 1; a(n) = Sum_{k=1..n} (-1)^(k+1)*sigma_2(k+1)*a(n-k), where sigma_2() is the sum of squares of divisors (A001157).

Table of values

List of values

A307242 a(0) = 1; a(n) = Sum_{k=1..n} (-1)^(k+1)sigma_2(k+1)a(n-k), where sigma_2() is the sum of squares of divisors (A001157).