A359808 - cp's OEIS frontend

A359808 a(n) is the least prime factor of the alternating factorial n! - (n-1)! + (n-2)! - ... 1! for n > 2; a(1) = a(2) = 1.

n	a(n)
1	1
2	1
3	5
4	19
5	101
6	619
7	4421
8	35899
9	79
10	3301819
11	13
12	29
13	47
14	23
15	1226280710981
16	53
17	47
18	2683
19	115578717622022981
20	8969
21	113
22	79
23	85439
24	12203
25	59
26	1657
27	127
28	61
29	661
30	47
31	173183
32	1117
33	83
34	4729
35	37
36	103
37	2858548279
38	59
39	67
40	431
41	32656499591185747972776747396512425885838364422981

[1, 1, 5, 19, 101, 619, 4421, 35899, 79, 3301819, 13, 29, 47, 23, 1226280710981, 53, 47, 2683, 115578717622022981, 8969, 113, 79, 85439, 12203, 59, 1657, 127, 61, 661, 47, 173183, 1117, 83, 4729, 37, 103, 2858548279, 59, 67, 431, 32656499591185747972776747396512425885838364422981]

cp's OEIS Frontend

A359808 a(n) is the least prime factor of the alternating factorial n! - (n-1)! + (n-2)! - ... 1! for n > 2; a(1) = a(2) = 1.

Table of values

List of values