A330322 - cp's OEIS frontend

A330322 a(n) = Sum_{i=1..n} sigma(i)*sigma(i+1), where sigma(n) = A000203(n) is the sum of the divisors of n.

n	a(n)
1	3
2	15
3	43
4	85
5	157
6	253
7	373
8	568
9	802
10	1018
11	1354
12	1746
13	2082
14	2658
15	3402
16	3960
17	4662
18	5442
19	6282
20	7626
21	8778
22	9642
23	11082
24	12942
25	14244
26	15924
27	18164
28	19844
29	22004
30	24308
31	26324
32	29348
33	31940
34	34532
35	38900
36	42358
37	44638
38	47998
39	53038
40	56818
41	60850

[3, 15, 43, 85, 157, 253, 373, 568, 802, 1018, 1354, 1746, 2082, 2658, 3402, 3960, 4662, 5442, 6282, 7626, 8778, 9642, 11082, 12942, 14244, 15924, 18164, 19844, 22004, 24308, 26324, 29348, 31940, 34532, 38900, 42358, 44638, 47998, 53038, 56818, 60850]

cp's OEIS Frontend

A330322 a(n) = Sum_{i=1..n} sigma(i)*sigma(i+1), where sigma(n) = A000203(n) is the sum of the divisors of n.

Table of values

List of values