OFFSET
2,3
EXAMPLE
a(2) = 1: 2 = 10 and 3 = 11, with a total of one 0.
a(3) = 1: 5 = 101, 7 = 111, again with just one 0.
MATHEMATICA
a[n_] := Sum[If[PrimeQ[k], DigitCount[k, 2, 0], 0], {k, 2^(n - 1), 2^n - 1}]; Array[a, 20, 2] (* Amiram Eldar, Jan 11 2020 *)
PROG
(PARI) a(n) = {nb = 0; for (i=2^(n-1), 2^n-1, if (isprime(i), nb += n - norml2(binary(i))); ); return (nb); } \\ Michel Marcus, Jun 20 2013
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Jacob Woolcutt (woolcutt(AT)uiuc.edu), Sep 19 2003
EXTENSIONS
a(27)-a(35) from Amiram Eldar, Jan 11 2020
STATUS
approved