A186440 - cp's OEIS frontend

A186440 Number of prime divisors (counted with multiplicity) of n such that the primitive irreducible trinomial x^n + x^k + 1 is a primitive irreducible polynomial (mod 2) for some k with 0 < k < n (A073726).

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

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

cp's OEIS Frontend

A186440 Number of prime divisors (counted with multiplicity) of n such that the primitive irreducible trinomial x^n + x^k + 1 is a primitive irreducible polynomial (mod 2) for some k with 0 < k < n (A073726).

Table of values

List of values

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

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

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