A349323 - cp's OEIS frontend

A349323 a(1)=1, a(2)=2, a(3)=4. Thereafter, for n>=3, a(n+1) is the smallest unused k such that d(k) is prime to both d(a(n)) and d(a(n-2)), but not to d(a(n-1)), where d is the divisor counting (tau) function A000005.

n	a(n)
1	1
2	2
3	4
4	3
5	9
6	5
7	25
8	6
9	36
10	7
11	49
12	8
13	100
14	10
15	121
16	11
17	144
18	13
19	16
20	14
21	81
22	12
23	625
24	15
25	1296
26	17
27	324
28	19
29	169
30	21
31	196
32	22
33	225
34	23
35	256
36	24
37	289
38	26
39	361
40	27
41	400
42	29
43	441
44	30
45	484
46	31
47	529
48	33
49	576
50	34
51	64
52	35
53	729
54	18
55	5184
56	20
57	2401
58	28
59	10000
60	32
61	11664

[1, 2, 4, 3, 9, 5, 25, 6, 36, 7, 49, 8, 100, 10, 121, 11, 144, 13, 16, 14, 81, 12, 625, 15, 1296, 17, 324, 19, 169, 21, 196, 22, 225, 23, 256, 24, 289, 26, 361, 27, 400, 29, 441, 30, 484, 31, 529, 33, 576, 34, 64, 35, 729, 18, 5184, 20, 2401, 28, 10000, 32, 11664]

cp's OEIS Frontend

A349323 a(1)=1, a(2)=2, a(3)=4. Thereafter, for n>=3, a(n+1) is the smallest unused k such that d(k) is prime to both d(a(n)) and d(a(n-2)), but not to d(a(n-1)), where d is the divisor counting (tau) function A000005.

Table of values

List of values