A211659 - cp's OEIS frontend

A211659 Numbers k such that k and k+1 both have unique values of sigma(k) and sigma(k+1); sigma(k) = A000203(k) = sum of divisors of k.

n	a(n)
1	1
2	2
3	3
4	4
5	7
6	8
7	12
8	18
9	36
10	49
11	72
12	100
13	128
14	133
15	148
16	162
17	192
18	199
19	217
20	218
21	256
22	288
23	313
24	337
25	400
26	421
27	457
28	511
29	547
30	548
31	562
32	576
33	577
34	578
35	652
36	661
37	676
38	721
39	841
40	842
41	871
42	876
43	1058
44	1093
45	1152
46	1171
47	1191
48	1200
49	1227
50	1233
51	1249
52	1282
53	1306

[1, 2, 3, 4, 7, 8, 12, 18, 36, 49, 72, 100, 128, 133, 148, 162, 192, 199, 217, 218, 256, 288, 313, 337, 400, 421, 457, 511, 547, 548, 562, 576, 577, 578, 652, 661, 676, 721, 841, 842, 871, 876, 1058, 1093, 1152, 1171, 1191, 1200, 1227, 1233, 1249, 1282, 1306]

cp's OEIS Frontend

A211659 Numbers k such that k and k+1 both have unique values of sigma(k) and sigma(k+1); sigma(k) = A000203(k) = sum of divisors of k.

Table of values

List of values