A127200 Numerator of n-th partial sum of the Van der Waerden-Ulam binary measure of the primes.

1, 1, 5, 23, 49, 51, 13, 105, 211, 1693, 3391, 1697, 6791, 13585, 27173, 108699, 217405, 217409, 217411, 54353, 434825, 6957209, 13914427, 27828863, 55657735, 111315479, 222630967, 55657743, 445261949, 1781047807, 3562095625

Offset: 2

Author

Artur Jasinski, Jan 08 2007

Keywords

• nonn
• frac

Crossrefs

Cf. A119523, A127197, A127201.

Programs

Mathematica

Table[Numerator[Sum[PrimePi[k]/2^k, {k, 2, x}]], {x, 2, 100}]

PARI

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