A190612 - cp's OEIS frontend

A190612 Numbers k such that (tau(k-1) + tau(k+1))/tau(k) is an integer, where tau(k)=A000005(k).

n	a(n)
1	6
2	7
3	11
4	13
5	19
6	20
7	23
8	25
9	28
10	29
11	31
12	32
13	34
14	39
15	41
16	43
17	46
18	47
19	51
20	52
21	53
22	55
23	56
24	57
25	59
26	61
27	62
28	67
29	68
30	71
31	73
32	74
33	79
34	83
35	85
36	86
37	87
38	89
39	94
40	95
41	97
42	103
43	107
44	109
45	113
46	119
47	127
48	129
49	131
50	133
51	134
52	137
53	139
54	141
55	142
56	149
57	151
58	152
59	155
60	157

[6, 7, 11, 13, 19, 20, 23, 25, 28, 29, 31, 32, 34, 39, 41, 43, 46, 47, 51, 52, 53, 55, 56, 57, 59, 61, 62, 67, 68, 71, 73, 74, 79, 83, 85, 86, 87, 89, 94, 95, 97, 103, 107, 109, 113, 119, 127, 129, 131, 133, 134, 137, 139, 141, 142, 149, 151, 152, 155, 157]

cp's OEIS Frontend

A190612 Numbers k such that (tau(k-1) + tau(k+1))/tau(k) is an integer, where tau(k)=A000005(k).

Table of values

List of values

n	a(n)
1	6
2	7
3	11
4	13
5	19
6	20
7	23
8	25
9	28
10	29
11	31
12	32
13	34
14	39
15	41
16	43
17	46
18	47
19	51
20	52
21	53
22	55
23	56
24	57
25	59
26	61
27	62
28	67
29	68
30	71
31	73
32	74
33	79
34	83
35	85
36	86
37	87
38	89
39	94
40	95
41	97
42	103
43	107
44	109
45	113
46	119
47	127
48	129
49	131
50	133
51	134
52	137
53	139
54	141
55	142
56	149
57	151
58	152
59	155
60	157

n	a(n)
1	6
2	7
3	11
4	13
5	19
6	20
7	23
8	25
9	28
10	29
11	31
12	32
13	34
14	39
15	41
16	43
17	46
18	47
19	51
20	52
21	53
22	55
23	56
24	57
25	59
26	61
27	62
28	67
29	68
30	71
31	73
32	74
33	79
34	83
35	85
36	86
37	87
38	89
39	94
40	95
41	97
42	103
43	107
44	109
45	113
46	119
47	127
48	129
49	131
50	133
51	134
52	137
53	139
54	141
55	142
56	149
57	151
58	152
59	155
60	157

n	a(n)
1	6
2	7
3	11
4	13
5	19
6	20
7	23
8	25
9	28
10	29
11	31
12	32
13	34
14	39
15	41
16	43
17	46
18	47
19	51
20	52
21	53
22	55
23	56
24	57
25	59
26	61
27	62
28	67
29	68
30	71
31	73
32	74
33	79
34	83
35	85
36	86
37	87
38	89
39	94
40	95
41	97
42	103
43	107
44	109
45	113
46	119
47	127
48	129
49	131
50	133
51	134
52	137
53	139
54	141
55	142
56	149
57	151
58	152
59	155
60	157