A223138 - cp's OEIS frontend

A223138 Numbers n such that sigma(n+1) - sigma(n-1) = n / k for some integer, where sigma(n) = A000203 (sum of divisors of n).

n	a(n)
1	4
2	5
3	6
4	9
5	10
6	12
7	18
8	30
9	32
10	42
11	54
12	56
13	60
14	72
15	101
16	102
17	108
18	129
19	138
20	144
21	150
22	172
23	176
24	180
25	192
26	198
27	204
28	216
29	220
30	228
31	240
32	252
33	270
34	282
35	312
36	348
37	384
38	420
39	432
40	462
41	522
42	544
43	570
44	600
45	618
46	642
47	648
48	660
49	792
50	810
51	822
52	828
53	858
54	882
55	900
56	1020

[4, 5, 6, 9, 10, 12, 18, 30, 32, 42, 54, 56, 60, 72, 101, 102, 108, 129, 138, 144, 150, 172, 176, 180, 192, 198, 204, 216, 220, 228, 240, 252, 270, 282, 312, 348, 384, 420, 432, 462, 522, 544, 570, 600, 618, 642, 648, 660, 792, 810, 822, 828, 858, 882, 900, 1020]

cp's OEIS Frontend

A223138 Numbers n such that sigma(n+1) - sigma(n-1) = n / k for some integer, where sigma(n) = A000203 (sum of divisors of n).

Table of values

List of values