A187559 - OEIS

%I #6 Mar 30 2012 18:35:54

%S 2,3,5,7,2,3,5,7,2,3,5,7,3,5,7,11,13,17,19,2,5,11,17,23,29,3,7,11,19,

%T 23,31,19,29,5,11,17,23,29,41,47,53,59,13,41,7,23,31,47,71,79,17,53,

%U 71,89,19,29,59,79,89,2,2,5,11,17,23,29,11,31,41,17,31,59,73,23,41,59,29,73,3,3,7,11,19,23,31,11,31,41,19,47,61,23

%N Primes arising in A187234.

%e a(22) = 11 because A187234(22) = 123, and 1*2 + 1*3 + 2*3 = 11 is prime.

%p with(numtheory):T:=array(1..10):k:=1:for n from 1 to 1000 do:l:=length(n):n0:=n:for

%p   m from 1 to l do:q:=n0:u:=irem(q,10):v:=iquo(q,10):n0:=v :T[m]:=u:od: s:=0:

%p   for i from 1 to l-1 do: for j from i+1 to l do: s:=s+T[i]*T[j]:od: od:if type(s,prime)

%p   = true then printf(`%d, `,s):else fi:od:

%Y Cf. A187234.

%K nonn,base,easy

%O 1,1

%A _Michel Lagneau_, Mar 11 2011