A130319 - cp's OEIS frontend

A130319 Numbers k for which k!!/S(k) is an integer, where S(k) is the sum of all odd numbers less than or equal to k, if k is odd, or the sum of all even numbers less than or equal to k, if k is even.

n	a(n)
0	1
1	2
2	6
3	10
4	14
5	16
6	17
7	18
8	22
9	26
10	28
11	29
12	30
13	34
14	38
15	40
16	41
17	42
18	46
19	48
20	49
21	50
22	52
23	53
24	54
25	58
26	62
27	64
28	65
29	66
30	68
31	69
32	70
33	74
34	76
35	77
36	78
37	82
38	86
39	88
40	89
41	90
42	94
43	96
44	97
45	98
46	100
47	101
48	102
49	106
50	108
51	109
52	110
53	112
54	113
55	114
56	118
57	122
58	124
59	125
60	126
61	128

[1, 2, 6, 10, 14, 16, 17, 18, 22, 26, 28, 29, 30, 34, 38, 40, 41, 42, 46, 48, 49, 50, 52, 53, 54, 58, 62, 64, 65, 66, 68, 69, 70, 74, 76, 77, 78, 82, 86, 88, 89, 90, 94, 96, 97, 98, 100, 101, 102, 106, 108, 109, 110, 112, 113, 114, 118, 122, 124, 125, 126, 128]

cp's OEIS Frontend

A130319 Numbers k for which k!!/S(k) is an integer, where S(k) is the sum of all odd numbers less than or equal to k, if k is odd, or the sum of all even numbers less than or equal to k, if k is even.

Table of values

List of values

n	a(n)
0	1
1	2
2	6
3	10
4	14
5	16
6	17
7	18
8	22
9	26
10	28
11	29
12	30
13	34
14	38
15	40
16	41
17	42
18	46
19	48
20	49
21	50
22	52
23	53
24	54
25	58
26	62
27	64
28	65
29	66
30	68
31	69
32	70
33	74
34	76
35	77
36	78
37	82
38	86
39	88
40	89
41	90
42	94
43	96
44	97
45	98
46	100
47	101
48	102
49	106
50	108
51	109
52	110
53	112
54	113
55	114
56	118
57	122
58	124
59	125
60	126
61	128

n	a(n)
0	1
1	2
2	6
3	10
4	14
5	16
6	17
7	18
8	22
9	26
10	28
11	29
12	30
13	34
14	38
15	40
16	41
17	42
18	46
19	48
20	49
21	50
22	52
23	53
24	54
25	58
26	62
27	64
28	65
29	66
30	68
31	69
32	70
33	74
34	76
35	77
36	78
37	82
38	86
39	88
40	89
41	90
42	94
43	96
44	97
45	98
46	100
47	101
48	102
49	106
50	108
51	109
52	110
53	112
54	113
55	114
56	118
57	122
58	124
59	125
60	126
61	128

n	a(n)
0	1
1	2
2	6
3	10
4	14
5	16
6	17
7	18
8	22
9	26
10	28
11	29
12	30
13	34
14	38
15	40
16	41
17	42
18	46
19	48
20	49
21	50
22	52
23	53
24	54
25	58
26	62
27	64
28	65
29	66
30	68
31	69
32	70
33	74
34	76
35	77
36	78
37	82
38	86
39	88
40	89
41	90
42	94
43	96
44	97
45	98
46	100
47	101
48	102
49	106
50	108
51	109
52	110
53	112
54	113
55	114
56	118
57	122
58	124
59	125
60	126
61	128