OFFSET
1,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
EXAMPLE
Sum of digits of 15=6 not prime.
MATHEMATICA
Select[Range[250], !PrimeQ[Total[IntegerDigits[ # ]]]&] (* Vincenzo Librandi, Apr 17 2013 *)
PROG
(PARI) lista(n) = { my(x, y); for(x=1, n, y=sumdigits(x); if(!isprime(y), print1(x, ", ") ) ); }
CROSSREFS
KEYWORD
easy,nonn,base
AUTHOR
Cino Hilliard, Mar 13 2005
STATUS
approved