A249336 - cp's OEIS frontend

A249336 a(1) = 1; for n>1, a(n) = number of values k in range 1 .. n-1 such that {sum of prime indices in the prime factorization of a(k)} = {sum of prime indices in the prime factorization of a(n-1)}, both counted with multiplicity.

n	a(n)
1	1
2	1
3	2
4	1
5	3
6	1
7	4
8	2
9	2
10	3
11	3
12	4
13	5
14	1
15	5
16	2
17	4
18	6
19	3
20	7
21	1
22	6
23	4
24	8
25	5
26	6
27	7
28	2
29	5
30	8
31	9
32	3
33	9
34	4
35	10
36	5
37	10
38	6
39	11
40	1
41	7
42	7
43	8
44	12
45	9
46	10
47	11
48	2
49	6
50	13
51	1
52	8
53	14
54	3
55	11
56	4
57	12
58	12
59	13
60	2
61	7
62	14
63	5
64	15
65	6
66	16
67	15
68	7
69	16
70	17
71	1
72	9
73	18
74	8
75	17
76	2
77	8
78	18
79	9
80	19
81	1
82	10
83	20
84	10
85	21
86	3
87	13
88	4
89	14
90	11
91	12
92	22
93	5
94	19
95	2
96	9
97	23
98	1

[1, 1, 2, 1, 3, 1, 4, 2, 2, 3, 3, 4, 5, 1, 5, 2, 4, 6, 3, 7, 1, 6, 4, 8, 5, 6, 7, 2, 5, 8, 9, 3, 9, 4, 10, 5, 10, 6, 11, 1, 7, 7, 8, 12, 9, 10, 11, 2, 6, 13, 1, 8, 14, 3, 11, 4, 12, 12, 13, 2, 7, 14, 5, 15, 6, 16, 15, 7, 16, 17, 1, 9, 18, 8, 17, 2, 8, 18, 9, 19, 1, 10, 20, 10, 21, 3, 13, 4, 14, 11, 12, 22, 5, 19, 2, 9, 23, 1]

cp's OEIS Frontend

A249336 a(1) = 1; for n>1, a(n) = number of values k in range 1 .. n-1 such that {sum of prime indices in the prime factorization of a(k)} = {sum of prime indices in the prime factorization of a(n-1)}, both counted with multiplicity.

Table of values

List of values

n	a(n)
1	1
2	1
3	2
4	1
5	3
6	1
7	4
8	2
9	2
10	3
11	3
12	4
13	5
14	1
15	5
16	2
17	4
18	6
19	3
20	7
21	1
22	6
23	4
24	8
25	5
26	6
27	7
28	2
29	5
30	8
31	9
32	3
33	9
34	4
35	10
36	5
37	10
38	6
39	11
40	1
41	7
42	7
43	8
44	12
45	9
46	10
47	11
48	2
49	6
50	13
51	1
52	8
53	14
54	3
55	11
56	4
57	12
58	12
59	13
60	2
61	7
62	14
63	5
64	15
65	6
66	16
67	15
68	7
69	16
70	17
71	1
72	9
73	18
74	8
75	17
76	2
77	8
78	18
79	9
80	19
81	1
82	10
83	20
84	10
85	21
86	3
87	13
88	4
89	14
90	11
91	12
92	22
93	5
94	19
95	2
96	9
97	23
98	1

n	a(n)
1	1
2	1
3	2
4	1
5	3
6	1
7	4
8	2
9	2
10	3
11	3
12	4
13	5
14	1
15	5
16	2
17	4
18	6
19	3
20	7
21	1
22	6
23	4
24	8
25	5
26	6
27	7
28	2
29	5
30	8
31	9
32	3
33	9
34	4
35	10
36	5
37	10
38	6
39	11
40	1
41	7
42	7
43	8
44	12
45	9
46	10
47	11
48	2
49	6
50	13
51	1
52	8
53	14
54	3
55	11
56	4
57	12
58	12
59	13
60	2
61	7
62	14
63	5
64	15
65	6
66	16
67	15
68	7
69	16
70	17
71	1
72	9
73	18
74	8
75	17
76	2
77	8
78	18
79	9
80	19
81	1
82	10
83	20
84	10
85	21
86	3
87	13
88	4
89	14
90	11
91	12
92	22
93	5
94	19
95	2
96	9
97	23
98	1

n	a(n)
1	1
2	1
3	2
4	1
5	3
6	1
7	4
8	2
9	2
10	3
11	3
12	4
13	5
14	1
15	5
16	2
17	4
18	6
19	3
20	7
21	1
22	6
23	4
24	8
25	5
26	6
27	7
28	2
29	5
30	8
31	9
32	3
33	9
34	4
35	10
36	5
37	10
38	6
39	11
40	1
41	7
42	7
43	8
44	12
45	9
46	10
47	11
48	2
49	6
50	13
51	1
52	8
53	14
54	3
55	11
56	4
57	12
58	12
59	13
60	2
61	7
62	14
63	5
64	15
65	6
66	16
67	15
68	7
69	16
70	17
71	1
72	9
73	18
74	8
75	17
76	2
77	8
78	18
79	9
80	19
81	1
82	10
83	20
84	10
85	21
86	3
87	13
88	4
89	14
90	11
91	12
92	22
93	5
94	19
95	2
96	9
97	23
98	1