2,4

Table of n, a(n) for n=2..88.

Table[Numerator[PrimePi[k]/2^k], {k, 2, 1000}]

(PARI) a(n) = numerator(primepi(n)/2^n); \\ Michel Marcus, Oct 28 2019

Cf. A000079 (2^n), A000720 (PrimePi), A119523.

Sequence in context: A046533 A046532 A014421 * A114231 A079075 A086703

Adjacent sequences: A127194 A127195 A127196 * A127198 A127199 A127200

nonn,frac

Artur Jasinski, Jan 08 2007

Offset 2 from Michel Marcus, Oct 28 2019

approved