A223137 - cp's OEIS frontend

A223137 Numbers n such that sigma(n+1) - sigma(n-1) = k*n for some integer k, where sigma(n) = A000203 (sum of divisors of n).

n	a(n)
1	5
2	34
3	55
4	285
5	367
6	835
7	849
8	919
9	1241
10	1505
11	2911
12	2914
13	3305
14	4149
15	4188
16	6111
17	6903
18	7170
19	7913
20	9360
21	10251
22	10541
23	12566
24	15086
25	17273
26	17815
27	19005
28	19689
29	21411
30	21462
31	24882
32	25020
33	26610
34	28125
35	30593
36	30789
37	31485
38	38211
39	38983
40	39787
41	40311
42	45355

[5, 34, 55, 285, 367, 835, 849, 919, 1241, 1505, 2911, 2914, 3305, 4149, 4188, 6111, 6903, 7170, 7913, 9360, 10251, 10541, 12566, 15086, 17273, 17815, 19005, 19689, 21411, 21462, 24882, 25020, 26610, 28125, 30593, 30789, 31485, 38211, 38983, 39787, 40311, 45355]

cp's OEIS Frontend

A223137 Numbers n such that sigma(n+1) - sigma(n-1) = k*n for some integer k, where sigma(n) = A000203 (sum of divisors of n).

Table of values

List of values