A002120 - cp's OEIS frontend

A002120 a(1) = 0, a(2) = -2; for n > 2, a(n) + a(n-2) - a(n-3) - a(n-5) - ... - a(n-p) = (-1)^(n+1)*n if n is prime, otherwise = 0, where p = largest prime < n.

n	a(n)
1	0
2	-2
3	3
4	2
5	0
6	1
7	7
8	2
9	-6
10	8
11	22
12	-7
13	0
14	33
15	3
16	-14
17	51
18	46
19	-19
20	12
21	94
22	42
23	-23
24	113
25	150
26	-54
27	48
28	345
29	116
30	-109
31	403
32	498
33	-140
34	219
35	1057
36	326
37	-259
38	1271
39	1641
40	-308
41	656
42	3396
43	1161
44	-790
45	4269
46	5357
47	-987
48	2257
49	10934
50	3958
51	-1986
52	13678
53	17278
54	-2492
55	7447
56	35569
57	13778
58	-5860
59	44368
60	56403
61	-6405

[0, -2, 3, 2, 0, 1, 7, 2, -6, 8, 22, -7, 0, 33, 3, -14, 51, 46, -19, 12, 94, 42, -23, 113, 150, -54, 48, 345, 116, -109, 403, 498, -140, 219, 1057, 326, -259, 1271, 1641, -308, 656, 3396, 1161, -790, 4269, 5357, -987, 2257, 10934, 3958, -1986, 13678, 17278, -2492, 7447, 35569, 13778, -5860, 44368, 56403, -6405]

cp's OEIS Frontend

A002120 a(1) = 0, a(2) = -2; for n > 2, a(n) + a(n-2) - a(n-3) - a(n-5) - ... - a(n-p) = (-1)^(n+1)*n if n is prime, otherwise = 0, where p = largest prime < n.

Table of values

List of values