cp's OEIS Frontend

A154679 Primes p such that the sum of digits of p+2 is a composite number.

%I A154679 #11 Apr 28 2022 19:26:21
%S A154679 2,7,11,13,17,29,31,37,43,53,61,67,71,73,79,89,97,101,103,107,127,139,
%T A154679 151,157,163,167,179,181,193,211,223,229,233,241,251,257,269,271,277,
%U A154679 283,293,307,313,331,337,347,349,359,367,373,379,383,397,409,421,431
%N A154679 Primes p such that the sum of digits of p+2 is a composite number.
%C A154679 Primes p such that p+2 is in A104211. [_R. J. Mathar_, Jan 15 2009]
%H A154679 Robert Israel, <a href="/A154679/b154679.txt">Table of n, a(n) for n = 1..10000</a>
%p A154679 filter:= proc(n) local s;
%p A154679 if not isprime(n) then return false fi;
%p A154679 s:= convert(convert(n+2,base,10),`+`);
%p A154679 s >= 4 and not isprime(s)
%p A154679 end proc:
%p A154679 select(filter, [$2..1000]); # _Robert Israel_, Mar 13 2019
%t A154679 Select[Prime[Range[100]],CompositeQ[Total[IntegerDigits[#+2]]]&] (* _Harvey P. Dale_, Apr 28 2022 *)
%Y A154679 Cf. A007953, A104211.
%K A154679 base,easy,nonn
%O A154679 1,1
%A A154679 _Giovanni Teofilatto_, Jan 14 2009
%E A154679 Extended by _R. J. Mathar_, Jan 15 2009