A232178 - cp's OEIS frontend

A232178 Least k>=0 such that triangular(n) + k^2 is a square, or -1 if no such k exists.

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

[0, 0, 1, -1, -1, 1, 2, 6, 0, 2, 3, -1, -1, 3, 4, 1, 15, 4, 5, -1, -1, 5, 6, 20, 10, 6, 7, -1, -1, 7, 8, 27, 1, 8, 9, -1, -1, 9, 10, 2, 36, 10, 11, -1, -1, 11, 12, 41, 7, 0, 13, -1, -1, 13, 6, 24, 2, 14, 15, -1, -1, 15, 16, 3, 6, 8, 17, -1, -1, 17, 18, 62, 64, 18, 19]

cp's OEIS Frontend

A232178 Least k>=0 such that triangular(n) + k^2 is a square, or -1 if no such k exists.

Table of values

List of values

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

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

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