A347889 - cp's OEIS frontend

A347889 Numbers k such that sigma(k) > 2*k and A003415(sigma(k)) < k, where A003415 is the arithmetic derivative, and sigma is the sum of divisors function.

n	a(n)
1	18
2	36
3	100
4	144
5	324
6	400
7	576
8	784
9	900
10	1296
11	1458
12	1600
13	1936
14	2304
15	2500
16	2704
17	2916
18	3136
19	3600
20	4624
21	5184
22	5202
23	5776
24	6400
25	7744
26	8464
27	9216
28	9604
29	10000
30	10404
31	10816
32	11664
33	12100
34	13122
35	13456
36	14400
37	15376
38	17424
39	18496
40	19044
41	23104
42	25600
43	26244
44	28900
45	30258
46	30276
47	30976
48	32400
49	33856
50	36864
51	38416

[18, 36, 100, 144, 324, 400, 576, 784, 900, 1296, 1458, 1600, 1936, 2304, 2500, 2704, 2916, 3136, 3600, 4624, 5184, 5202, 5776, 6400, 7744, 8464, 9216, 9604, 10000, 10404, 10816, 11664, 12100, 13122, 13456, 14400, 15376, 17424, 18496, 19044, 23104, 25600, 26244, 28900, 30258, 30276, 30976, 32400, 33856, 36864, 38416]

cp's OEIS Frontend

A347889 Numbers k such that sigma(k) > 2*k and A003415(sigma(k)) < k, where A003415 is the arithmetic derivative, and sigma is the sum of divisors function.

Table of values

List of values