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A086904 Write the primes in binary; a(n) = total number of 0's in those which have an n-bit expansion. 1

%I

%S 1,1,2,7,13,35,71,147,298,622,1270,2558,5257,10509,21297,42852,86258,

%T 173528,348187,699590,1404936,2818606,5657411,11345622,22746823

%N Write the primes in binary; a(n) = total number of 0's in those which have an n-bit expansion.

%e a(2) = 1: 2 = 10 and 3 = 11, with a total of one 0.

%e a(3) = 1: 5 = 101, 7 = 111, again with just one 0.

%o (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

%Y Cf. A168156.

%K base,nonn

%O 2,3

%A Jacob Woolcutt (woolcutt(AT)uiuc.edu), Sep 19 2003

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Last modified November 21 09:14 EST 2019. Contains 329362 sequences. (Running on oeis4.)