A123901 - cp's OEIS frontend

A123901 a(n) = (n+3)/gcd(d(n), d(n+2)) where d(n) = cancellation factor in reducing Sum_{k=0..n} 1/k! to lowest terms.

n	a(n)
0	3
1	4
2	5
3	3
4	7
5	4
6	9
7	1
8	11
9	6
10	13
11	7
12	3
13	8
14	17
15	9
16	19
17	2
18	21
19	11
20	23
21	12
22	5
23	1
24	27
25	14
26	29
27	3
28	31
29	16
30	33
31	17
32	7
33	18
34	37
35	19
36	3
37	4
38	41
39	21
40	43
41	22
42	9
43	23
44	47
45	24
46	49
47	5
48	51
49	2
50	53
51	27
52	11
53	28
54	57
55	29
56	59
57	6
58	61
59	31
60	63
61	32
62	1
63	33
64	67
65	34
66	69
67	7
68	71
69	36
70	73
71	1
72	15
73	38
74	77
75	3
76	79
77	8
78	81

[3, 4, 5, 3, 7, 4, 9, 1, 11, 6, 13, 7, 3, 8, 17, 9, 19, 2, 21, 11, 23, 12, 5, 1, 27, 14, 29, 3, 31, 16, 33, 17, 7, 18, 37, 19, 3, 4, 41, 21, 43, 22, 9, 23, 47, 24, 49, 5, 51, 2, 53, 27, 11, 28, 57, 29, 59, 6, 61, 31, 63, 32, 1, 33, 67, 34, 69, 7, 71, 36, 73, 1, 15, 38, 77, 3, 79, 8, 81]

cp's OEIS Frontend

A123901 a(n) = (n+3)/gcd(d(n), d(n+2)) where d(n) = cancellation factor in reducing Sum_{k=0..n} 1/k! to lowest terms.

Table of values

List of values

n	a(n)
0	3
1	4
2	5
3	3
4	7
5	4
6	9
7	1
8	11
9	6
10	13
11	7
12	3
13	8
14	17
15	9
16	19
17	2
18	21
19	11
20	23
21	12
22	5
23	1
24	27
25	14
26	29
27	3
28	31
29	16
30	33
31	17
32	7
33	18
34	37
35	19
36	3
37	4
38	41
39	21
40	43
41	22
42	9
43	23
44	47
45	24
46	49
47	5
48	51
49	2
50	53
51	27
52	11
53	28
54	57
55	29
56	59
57	6
58	61
59	31
60	63
61	32
62	1
63	33
64	67
65	34
66	69
67	7
68	71
69	36
70	73
71	1
72	15
73	38
74	77
75	3
76	79
77	8
78	81

n	a(n)
0	3
1	4
2	5
3	3
4	7
5	4
6	9
7	1
8	11
9	6
10	13
11	7
12	3
13	8
14	17
15	9
16	19
17	2
18	21
19	11
20	23
21	12
22	5
23	1
24	27
25	14
26	29
27	3
28	31
29	16
30	33
31	17
32	7
33	18
34	37
35	19
36	3
37	4
38	41
39	21
40	43
41	22
42	9
43	23
44	47
45	24
46	49
47	5
48	51
49	2
50	53
51	27
52	11
53	28
54	57
55	29
56	59
57	6
58	61
59	31
60	63
61	32
62	1
63	33
64	67
65	34
66	69
67	7
68	71
69	36
70	73
71	1
72	15
73	38
74	77
75	3
76	79
77	8
78	81

n	a(n)
0	3
1	4
2	5
3	3
4	7
5	4
6	9
7	1
8	11
9	6
10	13
11	7
12	3
13	8
14	17
15	9
16	19
17	2
18	21
19	11
20	23
21	12
22	5
23	1
24	27
25	14
26	29
27	3
28	31
29	16
30	33
31	17
32	7
33	18
34	37
35	19
36	3
37	4
38	41
39	21
40	43
41	22
42	9
43	23
44	47
45	24
46	49
47	5
48	51
49	2
50	53
51	27
52	11
53	28
54	57
55	29
56	59
57	6
58	61
59	31
60	63
61	32
62	1
63	33
64	67
65	34
66	69
67	7
68	71
69	36
70	73
71	1
72	15
73	38
74	77
75	3
76	79
77	8
78	81