A190403 - cp's OEIS frontend

A190403 Number n for which sigma(n)=sigma(n'), where sigma is the sum of divisors and n' the arithmetic derivative of n.

n	a(n)
1	4
2	27
3	60
4	84
5	132
6	140
7	204
8	220
9	228
10	260
11	270
12	340
13	372
14	378
15	444
16	492
17	564
18	572
19	580
20	620
21	644
22	702
23	708
24	740
25	804
26	812
27	820
28	836
29	860
30	884
31	918
32	945
33	1026
34	1068
35	1180
36	1242
37	1276
38	1284
39	1292
40	1308
41	1316
42	1364
43	1420
44	1460
45	1484
46	1485
47	1508
48	1564
49	1566

[4, 27, 60, 84, 132, 140, 204, 220, 228, 260, 270, 340, 372, 378, 444, 492, 564, 572, 580, 620, 644, 702, 708, 740, 804, 812, 820, 836, 860, 884, 918, 945, 1026, 1068, 1180, 1242, 1276, 1284, 1292, 1308, 1316, 1364, 1420, 1460, 1484, 1485, 1508, 1564, 1566]

cp's OEIS Frontend

A190403 Number n for which sigma(n)=sigma(n'), where sigma is the sum of divisors and n' the arithmetic derivative of n.

Table of values

List of values