A366561 - cp's OEIS frontend

A366561 Triangle read by rows: T(n,k) = Sum_{y=1..n} Sum_{x=1..n} [GCD(f(x,y), n) = k], where f(x,y) = x^2 - y^2.

n	a(n)
1	1
2	2
3	2
4	4
5	0
6	5
7	8
8	0
9	0
10	8
11	16
12	0
13	0
14	0
15	9
16	8
17	8
18	10
19	0
20	0
21	10
22	36
23	0
24	0
25	0
26	0
27	0
28	13
29	32
30	0
31	0
32	8
33	0
34	0
35	0
36	24
37	36
38	0
39	24
40	0
41	0
42	0
43	0
44	0
45	21
46	32
47	32
48	0
49	0
50	18
51	0
52	0
53	0
54	0
55	18
56	100
57	0
58	0
59	0
60	0
61	0
62	0
63	0
64	0
65	0
66	21
67	32
68	0
69	40
70	32
71	0
72	0
73	0
74	0
75	0
76	0
77	0
78	40

[1, 2, 2, 4, 0, 5, 8, 0, 0, 8, 16, 0, 0, 0, 9, 8, 8, 10, 0, 0, 10, 36, 0, 0, 0, 0, 0, 13, 32, 0, 0, 8, 0, 0, 0, 24, 36, 0, 24, 0, 0, 0, 0, 0, 21, 32, 32, 0, 0, 18, 0, 0, 0, 0, 18, 100, 0, 0, 0, 0, 0, 0, 0, 0, 0, 21, 32, 0, 40, 32, 0, 0, 0, 0, 0, 0, 0, 40]

cp's OEIS Frontend

A366561 Triangle read by rows: T(n,k) = Sum_{y=1..n} Sum_{x=1..n} [GCD(f(x,y), n) = k], where f(x,y) = x^2 - y^2.

Table of values

List of values

n	a(n)
1	1
2	2
3	2
4	4
5	0
6	5
7	8
8	0
9	0
10	8
11	16
12	0
13	0
14	0
15	9
16	8
17	8
18	10
19	0
20	0
21	10
22	36
23	0
24	0
25	0
26	0
27	0
28	13
29	32
30	0
31	0
32	8
33	0
34	0
35	0
36	24
37	36
38	0
39	24
40	0
41	0
42	0
43	0
44	0
45	21
46	32
47	32
48	0
49	0
50	18
51	0
52	0
53	0
54	0
55	18
56	100
57	0
58	0
59	0
60	0
61	0
62	0
63	0
64	0
65	0
66	21
67	32
68	0
69	40
70	32
71	0
72	0
73	0
74	0
75	0
76	0
77	0
78	40

n	a(n)
1	1
2	2
3	2
4	4
5	0
6	5
7	8
8	0
9	0
10	8
11	16
12	0
13	0
14	0
15	9
16	8
17	8
18	10
19	0
20	0
21	10
22	36
23	0
24	0
25	0
26	0
27	0
28	13
29	32
30	0
31	0
32	8
33	0
34	0
35	0
36	24
37	36
38	0
39	24
40	0
41	0
42	0
43	0
44	0
45	21
46	32
47	32
48	0
49	0
50	18
51	0
52	0
53	0
54	0
55	18
56	100
57	0
58	0
59	0
60	0
61	0
62	0
63	0
64	0
65	0
66	21
67	32
68	0
69	40
70	32
71	0
72	0
73	0
74	0
75	0
76	0
77	0
78	40

n	a(n)
1	1
2	2
3	2
4	4
5	0
6	5
7	8
8	0
9	0
10	8
11	16
12	0
13	0
14	0
15	9
16	8
17	8
18	10
19	0
20	0
21	10
22	36
23	0
24	0
25	0
26	0
27	0
28	13
29	32
30	0
31	0
32	8
33	0
34	0
35	0
36	24
37	36
38	0
39	24
40	0
41	0
42	0
43	0
44	0
45	21
46	32
47	32
48	0
49	0
50	18
51	0
52	0
53	0
54	0
55	18
56	100
57	0
58	0
59	0
60	0
61	0
62	0
63	0
64	0
65	0
66	21
67	32
68	0
69	40
70	32
71	0
72	0
73	0
74	0
75	0
76	0
77	0
78	40