A031348 - cp's OEIS frontend

A031348 2-multiplicative persistence: number of iterations of "multiply 2nd powers of digits" needed to reach 0 or 1.

n	a(n)
1	0
2	7
3	6
4	6
5	3
6	5
7	5
8	4
9	5
10	1
11	1
12	7
13	6
14	6
15	3
16	5
17	5
18	4
19	5
20	1
21	7
22	6
23	5
24	4
25	2
26	4
27	5
28	3
29	4
30	1
31	6
32	5
33	5
34	4
35	3
36	4
37	4
38	3
39	4
40	1
41	6
42	4
43	4
44	3
45	2
46	3
47	3
48	2
49	4
50	1
51	3
52	2
53	3
54	2
55	3
56	2
57	3
58	2
59	2
60	1
61	5
62	4
63	4
64	3
65	2
66	4
67	5
68	2
69	4
70	1
71	5
72	5
73	4
74	3
75	3
76	5
77	2
78	5
79	4
80	1
81	4
82	3
83	3
84	2
85	2
86	2
87	5
88	2
89	3
90	1
91	5
92	4
93	4
94	4
95	2
96	4
97	4
98	3
99	3

[0, 7, 6, 6, 3, 5, 5, 4, 5, 1, 1, 7, 6, 6, 3, 5, 5, 4, 5, 1, 7, 6, 5, 4, 2, 4, 5, 3, 4, 1, 6, 5, 5, 4, 3, 4, 4, 3, 4, 1, 6, 4, 4, 3, 2, 3, 3, 2, 4, 1, 3, 2, 3, 2, 3, 2, 3, 2, 2, 1, 5, 4, 4, 3, 2, 4, 5, 2, 4, 1, 5, 5, 4, 3, 3, 5, 2, 5, 4, 1, 4, 3, 3, 2, 2, 2, 5, 2, 3, 1, 5, 4, 4, 4, 2, 4, 4, 3, 3]

cp's OEIS Frontend

A031348 2-multiplicative persistence: number of iterations of "multiply 2nd powers of digits" needed to reach 0 or 1.

Table of values

List of values

n	a(n)
1	0
2	7
3	6
4	6
5	3
6	5
7	5
8	4
9	5
10	1
11	1
12	7
13	6
14	6
15	3
16	5
17	5
18	4
19	5
20	1
21	7
22	6
23	5
24	4
25	2
26	4
27	5
28	3
29	4
30	1
31	6
32	5
33	5
34	4
35	3
36	4
37	4
38	3
39	4
40	1
41	6
42	4
43	4
44	3
45	2
46	3
47	3
48	2
49	4
50	1
51	3
52	2
53	3
54	2
55	3
56	2
57	3
58	2
59	2
60	1
61	5
62	4
63	4
64	3
65	2
66	4
67	5
68	2
69	4
70	1
71	5
72	5
73	4
74	3
75	3
76	5
77	2
78	5
79	4
80	1
81	4
82	3
83	3
84	2
85	2
86	2
87	5
88	2
89	3
90	1
91	5
92	4
93	4
94	4
95	2
96	4
97	4
98	3
99	3

n	a(n)
1	0
2	7
3	6
4	6
5	3
6	5
7	5
8	4
9	5
10	1
11	1
12	7
13	6
14	6
15	3
16	5
17	5
18	4
19	5
20	1
21	7
22	6
23	5
24	4
25	2
26	4
27	5
28	3
29	4
30	1
31	6
32	5
33	5
34	4
35	3
36	4
37	4
38	3
39	4
40	1
41	6
42	4
43	4
44	3
45	2
46	3
47	3
48	2
49	4
50	1
51	3
52	2
53	3
54	2
55	3
56	2
57	3
58	2
59	2
60	1
61	5
62	4
63	4
64	3
65	2
66	4
67	5
68	2
69	4
70	1
71	5
72	5
73	4
74	3
75	3
76	5
77	2
78	5
79	4
80	1
81	4
82	3
83	3
84	2
85	2
86	2
87	5
88	2
89	3
90	1
91	5
92	4
93	4
94	4
95	2
96	4
97	4
98	3
99	3

n	a(n)
1	0
2	7
3	6
4	6
5	3
6	5
7	5
8	4
9	5
10	1
11	1
12	7
13	6
14	6
15	3
16	5
17	5
18	4
19	5
20	1
21	7
22	6
23	5
24	4
25	2
26	4
27	5
28	3
29	4
30	1
31	6
32	5
33	5
34	4
35	3
36	4
37	4
38	3
39	4
40	1
41	6
42	4
43	4
44	3
45	2
46	3
47	3
48	2
49	4
50	1
51	3
52	2
53	3
54	2
55	3
56	2
57	3
58	2
59	2
60	1
61	5
62	4
63	4
64	3
65	2
66	4
67	5
68	2
69	4
70	1
71	5
72	5
73	4
74	3
75	3
76	5
77	2
78	5
79	4
80	1
81	4
82	3
83	3
84	2
85	2
86	2
87	5
88	2
89	3
90	1
91	5
92	4
93	4
94	4
95	2
96	4
97	4
98	3
99	3