A292936 - cp's OEIS frontend

A292936 a(n) = the least k >= 0 such that floor(n/(2^k)) is a nonprime; a(n) is degree of the "safeness" of prime, 0 if n is not a prime, 1 for unsafe primes (A059456), and k >= 2 for primes that are (k-1)-safe but not k-safe.

n	a(n)
1	0
2	1
3	1
4	0
5	2
6	0
7	2
8	0
9	0
10	0
11	3
12	0
13	1
14	0
15	0
16	0
17	1
18	0
19	1
20	0
21	0
22	0
23	4
24	0
25	0
26	0
27	0
28	0
29	1
30	0
31	1
32	0
33	0
34	0
35	0
36	0
37	1
38	0
39	0
40	0
41	1
42	0
43	1
44	0
45	0
46	0
47	5
48	0
49	0
50	0
51	0
52	0
53	1
54	0
55	0
56	0
57	0
58	0
59	2
60	0
61	1
62	0
63	0
64	0
65	0
66	0
67	1
68	0
69	0
70	0
71	1
72	0
73	1
74	0
75	0
76	0
77	0
78	0
79	1
80	0
81	0
82	0
83	2
84	0
85	0
86	0
87	0
88	0
89	1
90	0
91	0
92	0
93	0
94	0
95	0
96	0
97	1
98	0
99	0
100	0
101	1
102	0
103	1
104	0
105	0

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

cp's OEIS Frontend

A292936 a(n) = the least k >= 0 such that floor(n/(2^k)) is a nonprime; a(n) is degree of the "safeness" of prime, 0 if n is not a prime, 1 for unsafe primes (A059456), and k >= 2 for primes that are (k-1)-safe but not k-safe.

Table of values

List of values

n	a(n)
1	0
2	1
3	1
4	0
5	2
6	0
7	2
8	0
9	0
10	0
11	3
12	0
13	1
14	0
15	0
16	0
17	1
18	0
19	1
20	0
21	0
22	0
23	4
24	0
25	0
26	0
27	0
28	0
29	1
30	0
31	1
32	0
33	0
34	0
35	0
36	0
37	1
38	0
39	0
40	0
41	1
42	0
43	1
44	0
45	0
46	0
47	5
48	0
49	0
50	0
51	0
52	0
53	1
54	0
55	0
56	0
57	0
58	0
59	2
60	0
61	1
62	0
63	0
64	0
65	0
66	0
67	1
68	0
69	0
70	0
71	1
72	0
73	1
74	0
75	0
76	0
77	0
78	0
79	1
80	0
81	0
82	0
83	2
84	0
85	0
86	0
87	0
88	0
89	1
90	0
91	0
92	0
93	0
94	0
95	0
96	0
97	1
98	0
99	0
100	0
101	1
102	0
103	1
104	0
105	0

n	a(n)
1	0
2	1
3	1
4	0
5	2
6	0
7	2
8	0
9	0
10	0
11	3
12	0
13	1
14	0
15	0
16	0
17	1
18	0
19	1
20	0
21	0
22	0
23	4
24	0
25	0
26	0
27	0
28	0
29	1
30	0
31	1
32	0
33	0
34	0
35	0
36	0
37	1
38	0
39	0
40	0
41	1
42	0
43	1
44	0
45	0
46	0
47	5
48	0
49	0
50	0
51	0
52	0
53	1
54	0
55	0
56	0
57	0
58	0
59	2
60	0
61	1
62	0
63	0
64	0
65	0
66	0
67	1
68	0
69	0
70	0
71	1
72	0
73	1
74	0
75	0
76	0
77	0
78	0
79	1
80	0
81	0
82	0
83	2
84	0
85	0
86	0
87	0
88	0
89	1
90	0
91	0
92	0
93	0
94	0
95	0
96	0
97	1
98	0
99	0
100	0
101	1
102	0
103	1
104	0
105	0

n	a(n)
1	0
2	1
3	1
4	0
5	2
6	0
7	2
8	0
9	0
10	0
11	3
12	0
13	1
14	0
15	0
16	0
17	1
18	0
19	1
20	0
21	0
22	0
23	4
24	0
25	0
26	0
27	0
28	0
29	1
30	0
31	1
32	0
33	0
34	0
35	0
36	0
37	1
38	0
39	0
40	0
41	1
42	0
43	1
44	0
45	0
46	0
47	5
48	0
49	0
50	0
51	0
52	0
53	1
54	0
55	0
56	0
57	0
58	0
59	2
60	0
61	1
62	0
63	0
64	0
65	0
66	0
67	1
68	0
69	0
70	0
71	1
72	0
73	1
74	0
75	0
76	0
77	0
78	0
79	1
80	0
81	0
82	0
83	2
84	0
85	0
86	0
87	0
88	0
89	1
90	0
91	0
92	0
93	0
94	0
95	0
96	0
97	1
98	0
99	0
100	0
101	1
102	0
103	1
104	0
105	0