A211660 - cp's OEIS frontend

A211660 Numbers k such that k and k+2 both have unique values of sigma(k) and sigma(k+2); sigma(k) = A000203(k) = sum of divisors of k.

n	a(n)
1	1
2	2
3	3
4	5
5	7
6	27
7	43
8	98
9	146
10	169
11	171
12	197
13	200
14	217
15	241
16	257
17	281
18	331
19	347
20	379
21	386
22	409
23	448
24	461
25	487
26	505
27	507
28	509
29	547
30	554
31	576
32	577
33	641
34	800
35	821
36	829
37	841
38	857
39	907
40	937
41	1117
42	1250
43	1261
44	1283
45	1289
46	1322
47	1352
48	1359
49	1387
50	1415
51	1601
52	1621

[1, 2, 3, 5, 7, 27, 43, 98, 146, 169, 171, 197, 200, 217, 241, 257, 281, 331, 347, 379, 386, 409, 448, 461, 487, 505, 507, 509, 547, 554, 576, 577, 641, 800, 821, 829, 841, 857, 907, 937, 1117, 1250, 1261, 1283, 1289, 1322, 1352, 1359, 1387, 1415, 1601, 1621]

cp's OEIS Frontend

A211660 Numbers k such that k and k+2 both have unique values of sigma(k) and sigma(k+2); sigma(k) = A000203(k) = sum of divisors of k.

Table of values

List of values