A336761 - cp's OEIS frontend

A336761 a(0) = 0, a(1) = 1; for n > 1, a(n) = a(n-1) - lpf(n) if nonnegative and not already in the sequence, otherwise a(n) = a(n-1) + lpf(n), where lpf(n) is the least prime dividing n.

n	a(n)
0	0
1	1
2	3
3	6
4	4
5	9
6	7
7	14
8	12
9	15
10	13
11	2
12	4
13	17
14	19
15	16
16	18
17	35
18	33
19	52
20	50
21	47
22	45
23	22
24	20
25	25
26	23
27	26
28	24
29	53
30	51
31	82
32	80
33	77
34	75
35	70
36	68
37	31
38	29
39	32
40	30
41	71
42	69
43	112
44	110
45	107
46	105
47	58
48	56
49	49
50	51
51	48
52	46
53	99
54	97
55	92
56	90
57	87
58	85
59	144
60	142
61	81
62	79
63	76
64	74
65	79
66	81
67	148
68	146
69	143
70	141
71	212
72	210

[0, 1, 3, 6, 4, 9, 7, 14, 12, 15, 13, 2, 4, 17, 19, 16, 18, 35, 33, 52, 50, 47, 45, 22, 20, 25, 23, 26, 24, 53, 51, 82, 80, 77, 75, 70, 68, 31, 29, 32, 30, 71, 69, 112, 110, 107, 105, 58, 56, 49, 51, 48, 46, 99, 97, 92, 90, 87, 85, 144, 142, 81, 79, 76, 74, 79, 81, 148, 146, 143, 141, 212, 210]

cp's OEIS Frontend

A336761 a(0) = 0, a(1) = 1; for n > 1, a(n) = a(n-1) - lpf(n) if nonnegative and not already in the sequence, otherwise a(n) = a(n-1) + lpf(n), where lpf(n) is the least prime dividing n.

Table of values

List of values

n	a(n)
0	0
1	1
2	3
3	6
4	4
5	9
6	7
7	14
8	12
9	15
10	13
11	2
12	4
13	17
14	19
15	16
16	18
17	35
18	33
19	52
20	50
21	47
22	45
23	22
24	20
25	25
26	23
27	26
28	24
29	53
30	51
31	82
32	80
33	77
34	75
35	70
36	68
37	31
38	29
39	32
40	30
41	71
42	69
43	112
44	110
45	107
46	105
47	58
48	56
49	49
50	51
51	48
52	46
53	99
54	97
55	92
56	90
57	87
58	85
59	144
60	142
61	81
62	79
63	76
64	74
65	79
66	81
67	148
68	146
69	143
70	141
71	212
72	210

n	a(n)
0	0
1	1
2	3
3	6
4	4
5	9
6	7
7	14
8	12
9	15
10	13
11	2
12	4
13	17
14	19
15	16
16	18
17	35
18	33
19	52
20	50
21	47
22	45
23	22
24	20
25	25
26	23
27	26
28	24
29	53
30	51
31	82
32	80
33	77
34	75
35	70
36	68
37	31
38	29
39	32
40	30
41	71
42	69
43	112
44	110
45	107
46	105
47	58
48	56
49	49
50	51
51	48
52	46
53	99
54	97
55	92
56	90
57	87
58	85
59	144
60	142
61	81
62	79
63	76
64	74
65	79
66	81
67	148
68	146
69	143
70	141
71	212
72	210

n	a(n)
0	0
1	1
2	3
3	6
4	4
5	9
6	7
7	14
8	12
9	15
10	13
11	2
12	4
13	17
14	19
15	16
16	18
17	35
18	33
19	52
20	50
21	47
22	45
23	22
24	20
25	25
26	23
27	26
28	24
29	53
30	51
31	82
32	80
33	77
34	75
35	70
36	68
37	31
38	29
39	32
40	30
41	71
42	69
43	112
44	110
45	107
46	105
47	58
48	56
49	49
50	51
51	48
52	46
53	99
54	97
55	92
56	90
57	87
58	85
59	144
60	142
61	81
62	79
63	76
64	74
65	79
66	81
67	148
68	146
69	143
70	141
71	212
72	210