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%I #6 Mar 13 2015 19:17:44
%S 1,2,3,5,6,9,11,13,14,15,16,18,19,20,24,27,29,31,32,33,35,36,37,40,43,
%T 45,48,52,54,55,56,57,58,60,62,63,64,65,69,71,74,76,77,80,82,84,85,86,
%U 87,88,91,94,97,98,99,101,103,104,106,109,111,112,115,116,117,118,121
%N Numbers n such that the sum of the digits of the n-th lower twin prime is prime.
%e The 5th lower twin prime is 29. 2+9=11 a prime, so 5 is listed.
%e The 4th lower twin prime is 17. 1+7=8 so 4 is missing from the table.
%o (PARI) sdtwprime(n) = { local(x,y); for(x=1,n, y=sumdigits(twinl(x)); if(isprime(y), print1(x",") ) ) } sumdigits(n) = \ The sum of the digits of n { local(x,j,s=0); x=digits(n); for(j=1,length(x), s+=x[j]; ); return(s) } digits(n) = \ The vector of the digits of n { return(eval(Vec(Str(n)))) }
%K easy,nonn,base
%O 1,2
%A _Cino Hilliard_, Mar 13 2005
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