A156707 - cp's OEIS frontend

A156707 For all numbers k(n) congruent to +1 or -1 (mod 4) starting with k(n) = {3,5,7,9,11,...}, a(k(n)) is the congruence (mod 4) if k(n) is prime and 0 if k(n) is composite.

n	a(n)
1	-1
2	1
3	-1
4	0
5	-1
6	1
7	0
8	1
9	-1
10	0
11	-1
12	0
13	0
14	1
15	-1
16	0
17	0
18	1
19	0
20	1
21	-1
22	0
23	-1
24	0
25	0
26	1
27	0
28	0
29	-1
30	1
31	0
32	0
33	-1
34	0
35	-1
36	1
37	0
38	0
39	-1
40	0
41	-1
42	0
43	0
44	1
45	0
46	0
47	0
48	1
49	0
50	1
51	-1
52	0
53	-1
54	1
55	0
56	1
57	0
58	0
59	0
60	0
61	0
62	0
63	-1
64	0
65	-1
66	0
67	0
68	1
69	-1
70	0
71	0
72	0
73	0
74	1
75	-1
76	0
77	0
78	1
79	0
80	0
81	-1
82	0
83	-1
84	0
85	0
86	1
87	0
88	0
89	-1
90	1
91	0
92	0
93	0
94	0
95	-1

[-1, 1, -1, 0, -1, 1, 0, 1, -1, 0, -1, 0, 0, 1, -1, 0, 0, 1, 0, 1, -1, 0, -1, 0, 0, 1, 0, 0, -1, 1, 0, 0, -1, 0, -1, 1, 0, 0, -1, 0, -1, 0, 0, 1, 0, 0, 0, 1, 0, 1, -1, 0, -1, 1, 0, 1, 0, 0, 0, 0, 0, 0, -1, 0, -1, 0, 0, 1, -1, 0, 0, 0, 0, 1, -1, 0, 0, 1, 0, 0, -1, 0, -1, 0, 0, 1, 0, 0, -1, 1, 0, 0, 0, 0, -1]

cp's OEIS Frontend

A156707 For all numbers k(n) congruent to +1 or -1 (mod 4) starting with k(n) = {3,5,7,9,11,...}, a(k(n)) is the congruence (mod 4) if k(n) is prime and 0 if k(n) is composite.

Table of values

List of values

n	a(n)
1	-1
2	1
3	-1
4	0
5	-1
6	1
7	0
8	1
9	-1
10	0
11	-1
12	0
13	0
14	1
15	-1
16	0
17	0
18	1
19	0
20	1
21	-1
22	0
23	-1
24	0
25	0
26	1
27	0
28	0
29	-1
30	1
31	0
32	0
33	-1
34	0
35	-1
36	1
37	0
38	0
39	-1
40	0
41	-1
42	0
43	0
44	1
45	0
46	0
47	0
48	1
49	0
50	1
51	-1
52	0
53	-1
54	1
55	0
56	1
57	0
58	0
59	0
60	0
61	0
62	0
63	-1
64	0
65	-1
66	0
67	0
68	1
69	-1
70	0
71	0
72	0
73	0
74	1
75	-1
76	0
77	0
78	1
79	0
80	0
81	-1
82	0
83	-1
84	0
85	0
86	1
87	0
88	0
89	-1
90	1
91	0
92	0
93	0
94	0
95	-1

n	a(n)
1	-1
2	1
3	-1
4	0
5	-1
6	1
7	0
8	1
9	-1
10	0
11	-1
12	0
13	0
14	1
15	-1
16	0
17	0
18	1
19	0
20	1
21	-1
22	0
23	-1
24	0
25	0
26	1
27	0
28	0
29	-1
30	1
31	0
32	0
33	-1
34	0
35	-1
36	1
37	0
38	0
39	-1
40	0
41	-1
42	0
43	0
44	1
45	0
46	0
47	0
48	1
49	0
50	1
51	-1
52	0
53	-1
54	1
55	0
56	1
57	0
58	0
59	0
60	0
61	0
62	0
63	-1
64	0
65	-1
66	0
67	0
68	1
69	-1
70	0
71	0
72	0
73	0
74	1
75	-1
76	0
77	0
78	1
79	0
80	0
81	-1
82	0
83	-1
84	0
85	0
86	1
87	0
88	0
89	-1
90	1
91	0
92	0
93	0
94	0
95	-1

n	a(n)
1	-1
2	1
3	-1
4	0
5	-1
6	1
7	0
8	1
9	-1
10	0
11	-1
12	0
13	0
14	1
15	-1
16	0
17	0
18	1
19	0
20	1
21	-1
22	0
23	-1
24	0
25	0
26	1
27	0
28	0
29	-1
30	1
31	0
32	0
33	-1
34	0
35	-1
36	1
37	0
38	0
39	-1
40	0
41	-1
42	0
43	0
44	1
45	0
46	0
47	0
48	1
49	0
50	1
51	-1
52	0
53	-1
54	1
55	0
56	1
57	0
58	0
59	0
60	0
61	0
62	0
63	-1
64	0
65	-1
66	0
67	0
68	1
69	-1
70	0
71	0
72	0
73	0
74	1
75	-1
76	0
77	0
78	1
79	0
80	0
81	-1
82	0
83	-1
84	0
85	0
86	1
87	0
88	0
89	-1
90	1
91	0
92	0
93	0
94	0
95	-1