A355374 - cp's OEIS frontend

A355374 a(1) = 1; for n > 1, a(n) is the smallest positive number that has not yet appeared such that the number of proper divisors of a(n) equals the number of 1-bits in the binary expansion of a(n-1).

n	a(n)
1	1
2	2
3	3
4	4
5	5
6	9
7	25
8	6
9	49
10	8
11	7
12	10
13	121
14	12
15	169
16	16
17	11
18	14
19	15
20	81
21	21
22	22
23	26
24	27
25	625
26	18
27	289
28	33
29	361
30	20
31	529
32	34
33	841
34	28
35	35
36	38
37	39
38	2401
39	32
40	13
41	46
42	14641
43	24
44	961
45	44
46	51
47	28561
48	48
49	1369
50	64
51	17
52	1681
53	45
54	83521
55	729
56	15625
57	30
58	130321
59	1024
60	19
61	55
62	50
63	57
64	279841
65	117649

[1, 2, 3, 4, 5, 9, 25, 6, 49, 8, 7, 10, 121, 12, 169, 16, 11, 14, 15, 81, 21, 22, 26, 27, 625, 18, 289, 33, 361, 20, 529, 34, 841, 28, 35, 38, 39, 2401, 32, 13, 46, 14641, 24, 961, 44, 51, 28561, 48, 1369, 64, 17, 1681, 45, 83521, 729, 15625, 30, 130321, 1024, 19, 55, 50, 57, 279841, 117649]

cp's OEIS Frontend

A355374 a(1) = 1; for n > 1, a(n) is the smallest positive number that has not yet appeared such that the number of proper divisors of a(n) equals the number of 1-bits in the binary expansion of a(n-1).

Table of values

List of values