

A178327


Numbers k such that k^p+p is prime, where p is product of the digits of k.


1



1, 21, 6617, 12131, 12441, 114917, 121221, 124281, 125121, 145581, 172631, 182121, 191213, 211551, 221211, 221421, 241213, 293143, 421531, 421821
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,2


COMMENTS

All terms are odd. Large numbers corresponding to some terms are probable
prime. There is no further term up to 27500.
254597 < a(18) <= 293143. a(19) <= 421531. a(20) <= 421821.  Donovan Johnson, Aug 09 2010


LINKS



EXAMPLE

21^(2*1)+(2*1) is prime so 21 is a term.


MATHEMATICA

Do[p=Apply[Times, IntegerDigits[n]]; If[PrimeQ[n^p+p], Print[n]],
{n, 1, 27501, 2}]


CROSSREFS



KEYWORD

base,more,nonn


AUTHOR



EXTENSIONS



STATUS

approved



