A231901 - OEIS

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A231901

Least k > n such that k!/n! + 1 is a prime, or 0 if no such k exists.

1, 2, 4, 4, 6, 6, 11, 9, 11, 10, 20, 12, 15, 15, 16, 16, 18, 18, 23, 21, 22, 22, 40, 25, 27, 31, 28, 28, 37, 30, 42, 38, 34, 36, 42, 36, 110, 39, 43, 40, 42, 42, 56, 46, 50, 46, 55, 65, 51, 51, 53, 52, 55, 55, 73, 58, 58, 58, 60, 60, 63, 63, 177, 68, 70, 66, 82, 72

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,2

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

MATHEMATICA

Table[k = n + 1; While[! PrimeQ[k!/n! + 1], k++]; k, {n, 100}] (* T. D. Noe, Nov 18 2013 *)

PROG

(PARI) a(n) = {my(m = n+1); while(! isprime(m!/n! +1), m++); m; } \\ Michel Marcus, Mar 07 2014; corrected Jun 13 2022

CROSSREFS

Cf. A002981, A035093, A057217, A075757, A075758, A231549.

Sequence in context: A281072 A226951 A251557 * A135974 A153494 A352749

Adjacent sequences: A231898 A231899 A231900 * A231902 A231903 A231904

KEYWORD

nonn

AUTHOR

Alex Ratushnyak, Nov 15 2013

STATUS

approved