A386005 - cp's OEIS frontend

A386005 Number of stable digits of the integer tetration n^^n (i.e., maximum nonnegative integer m such that n^^n is congruent modulo 10^m to n^^(n + 1)), or -1 if n is a multiple of 10.

n	a(n)
2	0
3	2
4	3
5	12
6	7
7	12
8	7
9	9
10	-1
11	12
12	11
13	13
14	13
15	61
16	17
17	17
18	32
19	19
20	-1
21	22
22	20
23	22
24	46
25	78
26	54
27	26
28	27
29	29
30	-1
31	32
32	62
33	33
34	33
35	71
36	37
37	37
38	36
39	39
40	-1
41	42
42	40
43	84
44	43
45	92
46	47
47	46
48	47
49	98
50	-1
51	103
52	51
53	53
54	53
55	166
56	57
57	171
58	56
59	59
60	-1
61	62
62	60
63	62
64	63
65	396
66	67
67	66

[0, 2, 3, 12, 7, 12, 7, 9, -1, 12, 11, 13, 13, 61, 17, 17, 32, 19, -1, 22, 20, 22, 46, 78, 54, 26, 27, 29, -1, 32, 62, 33, 33, 71, 37, 37, 36, 39, -1, 42, 40, 84, 43, 92, 47, 46, 47, 98, -1, 103, 51, 53, 53, 166, 57, 171, 56, 59, -1, 62, 60, 62, 63, 396, 67, 66]

cp's OEIS Frontend

A386005 Number of stable digits of the integer tetration n^^n (i.e., maximum nonnegative integer m such that n^^n is congruent modulo 10^m to n^^(n + 1)), or -1 if n is a multiple of 10.

Table of values

List of values

n	a(n)
2	0
3	2
4	3
5	12
6	7
7	12
8	7
9	9
10	-1
11	12
12	11
13	13
14	13
15	61
16	17
17	17
18	32
19	19
20	-1
21	22
22	20
23	22
24	46
25	78
26	54
27	26
28	27
29	29
30	-1
31	32
32	62
33	33
34	33
35	71
36	37
37	37
38	36
39	39
40	-1
41	42
42	40
43	84
44	43
45	92
46	47
47	46
48	47
49	98
50	-1
51	103
52	51
53	53
54	53
55	166
56	57
57	171
58	56
59	59
60	-1
61	62
62	60
63	62
64	63
65	396
66	67
67	66

n	a(n)
2	0
3	2
4	3
5	12
6	7
7	12
8	7
9	9
10	-1
11	12
12	11
13	13
14	13
15	61
16	17
17	17
18	32
19	19
20	-1
21	22
22	20
23	22
24	46
25	78
26	54
27	26
28	27
29	29
30	-1
31	32
32	62
33	33
34	33
35	71
36	37
37	37
38	36
39	39
40	-1
41	42
42	40
43	84
44	43
45	92
46	47
47	46
48	47
49	98
50	-1
51	103
52	51
53	53
54	53
55	166
56	57
57	171
58	56
59	59
60	-1
61	62
62	60
63	62
64	63
65	396
66	67
67	66

n	a(n)
2	0
3	2
4	3
5	12
6	7
7	12
8	7
9	9
10	-1
11	12
12	11
13	13
14	13
15	61
16	17
17	17
18	32
19	19
20	-1
21	22
22	20
23	22
24	46
25	78
26	54
27	26
28	27
29	29
30	-1
31	32
32	62
33	33
34	33
35	71
36	37
37	37
38	36
39	39
40	-1
41	42
42	40
43	84
44	43
45	92
46	47
47	46
48	47
49	98
50	-1
51	103
52	51
53	53
54	53
55	166
56	57
57	171
58	56
59	59
60	-1
61	62
62	60
63	62
64	63
65	396
66	67
67	66