A248957 a(n) = PrimePi(4^n) - PrimePi(2^n).

0, 1, 4, 14, 48, 161, 546, 1869, 6488, 22903, 81853, 295638, 1077307, 3956781, 14628943, 54396516, 203273679, 762926860, 2874375515, 10866222782, 41203006771, 156660878622, 597116085785, 2280998189786, 8731187785599, 33483377539718, 128625499652666

Offset

0,3

Links

Jon E. Schoenfield, Table of n, a(n) for n = 0..43 (using the terms from the b-file at A007053)

Formula

a(n) = A007053(2*n) - A007053(n). - Jon E. Schoenfield, Apr 14 2018

Example

For n=3 one has PrimePi(4^3)-PrimePi(2^3) = 18-4 = 14.

Maple

with(numtheory): A248957:=n->pi(4^n)-pi(2^n): seq(A248957(n), n=0..12); # Wesley Ivan Hurt, Oct 17 2014

Mathematica

Table[PrimePi[4^n] - PrimePi[2^n], {n, 0, 15}] (* Wesley Ivan Hurt, Oct 17 2014 *)

Prog

(PARI) a(n) = primepi(4^n) - primepi(2^n); \\ Altug Alkan, Apr 14 2018

Crossrefs

Cf. A000720, A007053.

Sequence in context: A331319 A291254 A307127 * A127359 A289928 A007070

Adjacent sequences: A248954 A248955 A248956 * A248958 A248959 A248960

Keyword

nonn

Author

Oussama Moutaoikil, Oct 17 2014

Extensions

a(15)-a(16) from Jon E. Schoenfield, Oct 22 2014

a(17)-a(26) from Chai Wah Wu, Apr 14 2018

Status

approved