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
Programs
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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