%I A113478
%S A113478 0,1,4,11,28,64,173,438,1200,3325,9289,26494,76483,221530,645685
%N A113478 Number of cuban primes less than 10^n.
%H A113478 Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/
               CubanPrime.html">Cuban Prime</a>
%e A113478 7, 19, 37, 61, 127 are the first few cuban primes, so a(1)=1 and a(2)=4
%o A113478 (PARI) A113478(n)=sum(k=1,sqrt(10^n/3),isprime(3*k*(k+1)+1)) - M. F. 
               Hasler (Maximilian.Hasler(AT)gmail.com), Nov 28 2007
%Y A113478 Cf. A002407, A002504.
%Y A113478 Sequence in context: A014151 A096124 A090539 this_sequence A056601 A003230 
               A099326
%Y A113478 Adjacent sequences: A113475 A113476 A113477 this_sequence A113479 A113480 
               A113481
%K A113478 nonn,more
%O A113478 0,3
%A A113478 Eric Weisstein (eric(AT)weisstein.com), Jan 10, 2006