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A095006 Number of evil primes (A027699) in range ]2^n,2^(n+1)]. 6

%I #11 Feb 27 2017 21:39:50

%S 1,1,0,3,2,5,4,23,27,62,95,222,367,777,1269,2910,4859,10140,17714,

%T 36714,66020,133400,245959,493532,916913,1822087,3428633,6782008,

%U 12870735,25339113,48419194,95194890,182818705

%N Number of evil primes (A027699) in range ]2^n,2^(n+1)].

%H A. Karttunen and J. Moyer, <a href="/A095062/a095062.c.txt">C-program for computing the initial terms of this sequence</a>

%H <a href="/index/Pri#primesubsetpop2">Index entries for sequences related to occurrences of various subsets of primes in range ]2^n,2^(n+1)]</a>

%e From _Michael De Vlieger_, Feb 27 2017: (Start)

%e a(2) = 1 since between 2^2 and 2^3 only the prime 5 (binary 11) has an even number of 1s.

%e a(3) = 0 since none of the primes between 2^3 and 2^4 have an even number of 1s in their binary expansions.

%e a(4) = 3 since the primes 17, 23, and 29 have an even number of 1s in their binary expansions (i.e., 10001, 10111, 11101). (End)

%t Table[m = Count[Prime@ Range[PrimePi[2^n] + 1, PrimePi[2^(n + 1) - 1]], k_ /; EvenQ@ DigitCount[k, 2, 1]]; Print@ m; m, {n, 24}] (* _Michael De Vlieger_, Feb 27 2017 *)

%Y a(n) = A036378(n)-A095005(n).

%K nonn

%O 1,4

%A _Antti Karttunen_ and _Labos Elemer_, Jun 01 2004

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Last modified April 19 19:02 EDT 2024. Contains 371798 sequences. (Running on oeis4.)