OFFSET
1,1
LINKS
Sebastian Petzelberger, Table of n, a(n) for n = 1..10000
Carlos Rivera, PP&P Puzzle 24: Primes in several bases
MAPLE
f:= proc(b, x) local L, i;
L:= convert(x, base, b);
isprime(add(10^(i-1)*L[i], i=1..nops(L)))
end proc:
select(t -> not isprime(t) and nops(select(f, [$2..9], t))=2, [$1..1000]); # Robert Israel, Mar 26 2015
MATHEMATICA
fQ[n_] := CompositeQ@ n && Count[ CompositeQ[ FromDigits[ IntegerDigits[n, #]] & /@ Range[2, 9]], True] == 6; Select[ Range@ 500, fQ] (* Robert G. Wilson v, Mar 26 2015 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Sebastian Petzelberger, Mar 25 2015
STATUS
approved