|
| |
|
|
A055493
|
|
Numbers n such that Sum_{k=1..n} k! - 2 is prime.
|
|
0
| |
|
|
3, 4, 5, 12, 13, 19, 65, 90, 123, 211, 281, 459
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
COMMENTS
| There are no further terms in this sequence because for all n >= 466 (Sum_{k=1..n} k!) - 2 is divisible by 467. [From Dmitry Kamenetsky (dkamen(AT)rsise.anu.edu.au), Feb 10 2009]
|
|
|
EXAMPLE
| 1! + 2! + 3! + 4! + 5! -2 = 1 + 2 + 6 + 24 + 120 - 2 = 151 which is a prime.
|
|
|
MATHEMATICA
| Do[If[PrimeQ[Sum[m!, {m, 1, n}]-2], Print[n]], {n, 1, 2500}]
|
|
|
CROSSREFS
| Sequence in context: A173096 A046964 A191197 * A109350 A077034 A076601
Adjacent sequences: A055490 A055491 A055492 * A055494 A055495 A055496
|
|
|
KEYWORD
| nonn,fini,full
|
|
|
AUTHOR
| Robert G. Wilson v (rgwv(AT)rgwv.com), Jul 05 2000
|
| |
|
|
