

A288450


Numbers k such that k!6 + 48 is prime, where k!6 is the sextuple factorial number (A085158 ).


1



5, 11, 13, 17, 19, 35, 43, 49, 67, 71, 73, 85, 103, 263, 293, 497, 529, 599, 905, 971, 1685, 2927, 3635, 3847, 4535, 8501, 38777
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OFFSET

1,1


COMMENTS

Corresponding primes are: 53, 103, 139, 983, 1777, 21827623, 2131900273, 104463111073, ...
a(28) > 50000.
Terms > 49 correspond to probable primes.


LINKS

Table of n, a(n) for n=1..27.
Henri & Renaud Lifchitz, PRP Records. Search for n!6+48.
Joe McLean, Interesting Sources of Probable Primes
OpenPFGW Project, Primality Tester


EXAMPLE

11!6 + 48 = 11*5 + 48 = 103 is prime, so 11 is in the sequence.


MATHEMATICA

MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n  k, k]];
Select[Range[0, 50000], PrimeQ[MultiFactorial[#, 6] + 48] &]


CROSSREFS

Cf. A007661, A037082, A084438, A123910, A242994.
Sequence in context: A161548 A090320 A085909 * A272446 A307390 A104110
Adjacent sequences: A288447 A288448 A288449 * A288451 A288452 A288453


KEYWORD

nonn,more


AUTHOR

Robert Price, Jun 09 2017


STATUS

approved



