A301640 - cp's OEIS frontend

A301640 Largest integer k such that n^2 - 32^k can be written as x^2 + 2y^2 with x and y integers, or -1 if no such k exists.

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

[-1, 0, 1, 2, 3, 3, 4, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 7, 7, 7, 6, 7, 7, 7, 6, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 9, 8, 9, 9, 9, 9, 8, 9, 9, 7, 9, 7, 9, 9, 8, 9, 10, 10, 10, 10, 10, 10, 10, 9, 10, 10, 10, 9, 10, 10, 10]

cp's OEIS Frontend

A301640 Largest integer k such that n^2 - 32^k can be written as x^2 + 2y^2 with x and y integers, or -1 if no such k exists.

Table of values

List of values

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

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

cp's OEIS Frontend

A301640 Largest integer k such that n^2 - 3*2^k can be written as x^2 + 2*y^2 with x and y integers, or -1 if no such k exists.

Table of values

List of values

A301640 Largest integer k such that n^2 - 32^k can be written as x^2 + 2y^2 with x and y integers, or -1 if no such k exists.

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