A019565 - cp's OEIS frontend

A019565 The squarefree numbers ordered lexicographically by their prime factorization (with factors written in decreasing order). a(n) = Product_{k in I} prime(k+1), where I is the set of indices of nonzero binary digits in n = Sum_{k in I} 2^k.

n	a(n)
0	1
1	2
2	3
3	6
4	5
5	10
6	15
7	30
8	7
9	14
10	21
11	42
12	35
13	70
14	105
15	210
16	11
17	22
18	33
19	66
20	55
21	110
22	165
23	330
24	77
25	154
26	231
27	462
28	385
29	770
30	1155
31	2310
32	13
33	26
34	39
35	78
36	65
37	130
38	195
39	390
40	91
41	182
42	273
43	546
44	455
45	910
46	1365
47	2730
48	143
49	286
50	429
51	858
52	715
53	1430
54	2145
55	4290

[1, 2, 3, 6, 5, 10, 15, 30, 7, 14, 21, 42, 35, 70, 105, 210, 11, 22, 33, 66, 55, 110, 165, 330, 77, 154, 231, 462, 385, 770, 1155, 2310, 13, 26, 39, 78, 65, 130, 195, 390, 91, 182, 273, 546, 455, 910, 1365, 2730, 143, 286, 429, 858, 715, 1430, 2145, 4290]

cp's OEIS Frontend

A019565 The squarefree numbers ordered lexicographically by their prime factorization (with factors written in decreasing order). a(n) = Product_{k in I} prime(k+1), where I is the set of indices of nonzero binary digits in n = Sum_{k in I} 2^k.

Table of values

List of values