A227781 - cp's OEIS frontend

A227781 Least number of squares which add to -1 mod n.

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

[0, 1, 2, 3, 1, 2, 2, 4, 2, 1, 2, 3, 1, 2, 2, 4, 1, 2, 2, 3, 2, 2, 2, 4, 1, 1, 2, 3, 1, 2, 2, 4, 2, 1, 2, 3, 1, 2, 2, 4, 1, 2, 2, 3, 2, 2, 2, 4, 2, 1, 2, 3, 1, 2, 2, 4, 2, 1, 2, 3, 1, 2, 2, 4, 1, 2, 2, 3, 2, 2, 2, 4, 1, 1, 2, 3, 2, 2, 2, 4, 2, 1, 2, 3, 1, 2, 2, 4, 1, 2, 2, 3, 2, 2]

cp's OEIS Frontend

A227781 Least number of squares which add to -1 mod n.

Table of values

List of values

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

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

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