

A139057


Primes of the form (k!3)/3.


12




OFFSET

1,1


COMMENTS

Numbers k for which (k!  3)/3 is prime see A139056.
a(8) is 180 decimal digits long. See formula for more terms.  Derek Orr, Mar 28 2014


LINKS

Table of n, a(n) for n=1..7.


FORMULA

a(n) = (A139056(n)!3)/3 for all n.  Derek Orr, Mar 28 2014


MATHEMATICA

a = {}; Do[If[PrimeQ[(3 + n!!)/3], AppendTo[a, [(3 + n!!)/3]], {n, 1, 1000}]; a
Select[(Range[50]!3)/3, PrimeQ] (* Harvey P. Dale, Nov 27 2015 *)


PROG

(PARI) for(n=1, 1000, if(floor(n!/31)==n!/31, if(ispseudoprime(n!/31), print(n!/31)))) \\ Derek Orr, Mar 28 2014


CROSSREFS

Cf. A089085, A117141, A007749, A139056.
Sequence in context: A120661 A185389 A159967 * A251594 A210248 A200961
Adjacent sequences: A139054 A139055 A139056 * A139058 A139059 A139060


KEYWORD

nonn


AUTHOR

Artur Jasinski, Apr 07 2008


EXTENSIONS

Definition corrected by Derek Orr, Mar 28 2014


STATUS

approved



