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%I #11 May 06 2018 00:43:04
%S 7,19,37,41,47,71,83,91,103,127,157,161,187,199,203,209,239,257,281,
%T 293,311,349,371,377,391,413,421,433,463,467,479,491,511,539,547,551,
%U 587,619,629,661,677,689,721,749,769,787,791,803,817,859,871,883,923
%N Numbers that yield a prime when a 9 is prefixed or suffixed to them.
%e 127 is a member as both 1279 and 9127 are primes.
%p i := 0:for k from 1 to 3200 do if(isprime(9+10*k) and isprime(k+10^(ceil(evalf(log(k+1)/log(10))))*9)) then s[i] := k; i := i+1; end if; end do:q := seq(s[j],j=0..i-1);
%Y Cf. A068673, A068674, A068677.
%K base,easy,nonn
%O 1,1
%A _Amarnath Murthy_, Mar 02 2002
%E More terms from _Sascha Kurz_, Mar 17 2002