A319478 - cp's OEIS frontend

A319478 a(n) is the least base b > 1 such that the product n * n can be computed without carry by long multiplication.

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

[2, 2, 2, 3, 2, 4, 5, 5, 2, 3, 3, 5, 3, 6, 7, 7, 2, 4, 9, 9, 4, 4, 10, 11, 11, 5, 5, 3, 3, 13, 3, 3, 2, 11, 11, 5, 3, 3, 6, 13, 13, 13, 6, 6, 6, 15, 15, 15, 6, 7, 5, 5, 17, 17, 18, 5, 7, 7, 7, 19, 19, 20, 20, 7, 2, 4, 8, 22, 4, 4, 17, 23, 6, 6, 8, 24, 19, 19, 6]

cp's OEIS Frontend

A319478 a(n) is the least base b > 1 such that the product n * n can be computed without carry by long multiplication.

Table of values

List of values

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

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

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