0,2

H. J. Smith, XICalc - Extra Precision Integer Calculator.

a(n) = PiPrime(2^(2^n))

a(3) = 54 because 2^(2^3) = 256 and there are 54 primes <= 256.

(Other) (XICalc) Pi(2^(2^n));

A001146

Sequence in context: A085078 A152543 A122593 this_sequence A084123 A074023 A000146

Adjacent sequences: A153447 A153448 A153449 this_sequence A153451 A153452 A153453

nonn

Harry J. Smith (hjsmithh(AT)sbcglobal.net), Dec 27 2008