A337903 - cp's OEIS frontend

A337903 a(0) = 0, a(1) = 1; for n>1, if a(n-1) is composite then a(n) = a(n-1)/A107286(n-1), where A107286(n) = the smallest prime factor of n, otherwise a(n) = a(n-1) + n.

n	a(n)
0	0
1	1
2	3
3	6
4	3
5	8
6	4
7	2
8	10
9	5
10	15
11	5
12	17
13	30
14	15
15	5
16	21
17	7
18	25
19	5
20	25
21	5
22	27
23	9
24	3
25	28
26	14
27	7
28	35
29	7
30	37
31	68
32	34
33	17
34	51
35	17
36	53
37	90
38	45
39	15
40	5
41	46
42	23
43	66
44	33
45	11
46	57
47	19
48	67
49	116
50	58
51	29
52	81
53	27
54	9
55	3
56	59
57	116
58	58
59	29
60	89
61	150
62	75
63	25
64	5
65	70
66	35
67	7
68	75
69	25
70	5
71	76
72	38
73	19
74	93
75	31
76	107
77	184
78	92

[0, 1, 3, 6, 3, 8, 4, 2, 10, 5, 15, 5, 17, 30, 15, 5, 21, 7, 25, 5, 25, 5, 27, 9, 3, 28, 14, 7, 35, 7, 37, 68, 34, 17, 51, 17, 53, 90, 45, 15, 5, 46, 23, 66, 33, 11, 57, 19, 67, 116, 58, 29, 81, 27, 9, 3, 59, 116, 58, 29, 89, 150, 75, 25, 5, 70, 35, 7, 75, 25, 5, 76, 38, 19, 93, 31, 107, 184, 92]

cp's OEIS Frontend

A337903 a(0) = 0, a(1) = 1; for n>1, if a(n-1) is composite then a(n) = a(n-1)/A107286(n-1), where A107286(n) = the smallest prime factor of n, otherwise a(n) = a(n-1) + n.

Table of values

List of values

n	a(n)
0	0
1	1
2	3
3	6
4	3
5	8
6	4
7	2
8	10
9	5
10	15
11	5
12	17
13	30
14	15
15	5
16	21
17	7
18	25
19	5
20	25
21	5
22	27
23	9
24	3
25	28
26	14
27	7
28	35
29	7
30	37
31	68
32	34
33	17
34	51
35	17
36	53
37	90
38	45
39	15
40	5
41	46
42	23
43	66
44	33
45	11
46	57
47	19
48	67
49	116
50	58
51	29
52	81
53	27
54	9
55	3
56	59
57	116
58	58
59	29
60	89
61	150
62	75
63	25
64	5
65	70
66	35
67	7
68	75
69	25
70	5
71	76
72	38
73	19
74	93
75	31
76	107
77	184
78	92

n	a(n)
0	0
1	1
2	3
3	6
4	3
5	8
6	4
7	2
8	10
9	5
10	15
11	5
12	17
13	30
14	15
15	5
16	21
17	7
18	25
19	5
20	25
21	5
22	27
23	9
24	3
25	28
26	14
27	7
28	35
29	7
30	37
31	68
32	34
33	17
34	51
35	17
36	53
37	90
38	45
39	15
40	5
41	46
42	23
43	66
44	33
45	11
46	57
47	19
48	67
49	116
50	58
51	29
52	81
53	27
54	9
55	3
56	59
57	116
58	58
59	29
60	89
61	150
62	75
63	25
64	5
65	70
66	35
67	7
68	75
69	25
70	5
71	76
72	38
73	19
74	93
75	31
76	107
77	184
78	92

n	a(n)
0	0
1	1
2	3
3	6
4	3
5	8
6	4
7	2
8	10
9	5
10	15
11	5
12	17
13	30
14	15
15	5
16	21
17	7
18	25
19	5
20	25
21	5
22	27
23	9
24	3
25	28
26	14
27	7
28	35
29	7
30	37
31	68
32	34
33	17
34	51
35	17
36	53
37	90
38	45
39	15
40	5
41	46
42	23
43	66
44	33
45	11
46	57
47	19
48	67
49	116
50	58
51	29
52	81
53	27
54	9
55	3
56	59
57	116
58	58
59	29
60	89
61	150
62	75
63	25
64	5
65	70
66	35
67	7
68	75
69	25
70	5
71	76
72	38
73	19
74	93
75	31
76	107
77	184
78	92