A260422 - cp's OEIS frontend

A260422 a(1) = 1, a(2n) = A205783(1+a(n)), a(2n+1) = A206074(a(n)), where A206074 and A205783 give binary codes for polynomials with coefficients 0 or 1 that are irreducible [resp. reducible] over Q.

n	a(n)
1	1
2	4
3	2
4	9
5	7
6	6
7	3
8	16
9	23
10	14
11	17
12	12
13	13
14	8
15	5
16	27
17	47
18	36
19	71
20	24
21	41
22	28
23	53
24	21
25	31
26	22
27	37
28	15
29	19
30	10
31	11
32	42
33	81
34	70
35	149
36	54
37	109
38	106
39	239
40	38
41	73
42	62
43	127
44	44
45	83
46	80
47	171
48	34
49	67
50	48
51	91
52	35
53	69
54	56
55	113
56	26
57	43
58	32
59	59
60	18
61	25
62	20
63	29
64	63
65	131
66	122
67	271
68	105
69	233
70	216
71	477
72	82
73	173
74	159
75	353
76	155
77	347
78	345
79	787
80	57

[1, 4, 2, 9, 7, 6, 3, 16, 23, 14, 17, 12, 13, 8, 5, 27, 47, 36, 71, 24, 41, 28, 53, 21, 31, 22, 37, 15, 19, 10, 11, 42, 81, 70, 149, 54, 109, 106, 239, 38, 73, 62, 127, 44, 83, 80, 171, 34, 67, 48, 91, 35, 69, 56, 113, 26, 43, 32, 59, 18, 25, 20, 29, 63, 131, 122, 271, 105, 233, 216, 477, 82, 173, 159, 353, 155, 347, 345, 787, 57]

cp's OEIS Frontend

A260422 a(1) = 1, a(2n) = A205783(1+a(n)), a(2n+1) = A206074(a(n)), where A206074 and A205783 give binary codes for polynomials with coefficients 0 or 1 that are irreducible [resp. reducible] over Q.

Table of values

List of values

n	a(n)
1	1
2	4
3	2
4	9
5	7
6	6
7	3
8	16
9	23
10	14
11	17
12	12
13	13
14	8
15	5
16	27
17	47
18	36
19	71
20	24
21	41
22	28
23	53
24	21
25	31
26	22
27	37
28	15
29	19
30	10
31	11
32	42
33	81
34	70
35	149
36	54
37	109
38	106
39	239
40	38
41	73
42	62
43	127
44	44
45	83
46	80
47	171
48	34
49	67
50	48
51	91
52	35
53	69
54	56
55	113
56	26
57	43
58	32
59	59
60	18
61	25
62	20
63	29
64	63
65	131
66	122
67	271
68	105
69	233
70	216
71	477
72	82
73	173
74	159
75	353
76	155
77	347
78	345
79	787
80	57

n	a(n)
1	1
2	4
3	2
4	9
5	7
6	6
7	3
8	16
9	23
10	14
11	17
12	12
13	13
14	8
15	5
16	27
17	47
18	36
19	71
20	24
21	41
22	28
23	53
24	21
25	31
26	22
27	37
28	15
29	19
30	10
31	11
32	42
33	81
34	70
35	149
36	54
37	109
38	106
39	239
40	38
41	73
42	62
43	127
44	44
45	83
46	80
47	171
48	34
49	67
50	48
51	91
52	35
53	69
54	56
55	113
56	26
57	43
58	32
59	59
60	18
61	25
62	20
63	29
64	63
65	131
66	122
67	271
68	105
69	233
70	216
71	477
72	82
73	173
74	159
75	353
76	155
77	347
78	345
79	787
80	57

n	a(n)
1	1
2	4
3	2
4	9
5	7
6	6
7	3
8	16
9	23
10	14
11	17
12	12
13	13
14	8
15	5
16	27
17	47
18	36
19	71
20	24
21	41
22	28
23	53
24	21
25	31
26	22
27	37
28	15
29	19
30	10
31	11
32	42
33	81
34	70
35	149
36	54
37	109
38	106
39	239
40	38
41	73
42	62
43	127
44	44
45	83
46	80
47	171
48	34
49	67
50	48
51	91
52	35
53	69
54	56
55	113
56	26
57	43
58	32
59	59
60	18
61	25
62	20
63	29
64	63
65	131
66	122
67	271
68	105
69	233
70	216
71	477
72	82
73	173
74	159
75	353
76	155
77	347
78	345
79	787
80	57