|
| |
|
|
A298702
|
|
Numbers k such that k!+1 reversed is a prime.
|
|
1
|
|
|
|
1, 2, 3, 6, 11, 15, 17, 19, 22, 51, 867, 1909, 9641
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
1,2
|
|
|
COMMENTS
|
a(14) > 19200, if it exists. - Giovanni Resta, May 04 2018
|
|
|
LINKS
|
Table of n, a(n) for n=1..13.
|
|
|
MATHEMATICA
|
Do[If[PrimeQ[FromDigits[Reverse[IntegerDigits[n! + 1]]]], Print[n]], {n, 400}] (* Vincenzo Librandi, Jan 25 2018 *)
|
|
|
PROG
|
(PARI) isok(n) = isprime(fromdigits(Vecrev(digits(n!+1)))); \\ Michel Marcus, Jan 26 2018
|
|
|
CROSSREFS
|
Cf. A002981.
Sequence in context: A163781 A090304 A005211 * A076307 A102990 A138519
Adjacent sequences: A298699 A298700 A298701 * A298703 A298704 A298705
|
|
|
KEYWORD
|
nonn,base,more
|
|
|
AUTHOR
|
Paolo Galliani, Jan 25 2018
|
|
|
EXTENSIONS
|
a(1)-a(3) and a(8)-a(10) from Vincenzo Librandi, Jan 25 2018
a(11)-a(12) from Paolo Galliani, May 02 2018
a(13) from Giovanni Resta, May 04 2018
|
|
|
STATUS
|
approved
|
| |
|
|
