A095282 - OEIS

%I #18 Dec 15 2019 10:36:19

%S 2,3,11,19,43,47,59,67,79,83,107,131,139,163,179,191,211,227,239,251,

%T 271,283,307,331,347,367,379,419,431,443,463,467,491,499,523,547,563,

%U 571,587,619,643,659,683,691,719,739,751,787,811,827,859

%N Primes whose binary-expansion ends with an even number of 1's.

%H Charles R Greathouse IV, <a href="/A095282/b095282.txt">Table of n, a(n) for n = 1..10000</a>

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

%p q:= proc(n) local i, l, r; l, r:= convert(n, base, 2), 0;

%p       for i to nops(l) while l[i]=1 do r:=r+1 od; is(r, even)

%p     end:

%p select(q, [ithprime(i)$i=1..200])[];  # _Alois P. Heinz_, Dec 15 2019

%t been1Q[n_]:=Module[{c=Split[IntegerDigits[n,2]][[-1]]},c[[1]]==1&&EvenQ[ Length[ c]]]; Join[{2},Select[Prime[Range[150]],been1Q]] (* _Harvey P. Dale_, Dec 14 2019 *)

%o (PARI) is(n)=valuation(n+1,2)%2==0 && isprime(n) \\ _Charles R Greathouse IV_, Oct 09 2013

%Y Intersection of A000040 & (complement of A079523). Complement of A095283 in A000040. Cf. A027699, A095292.

%K nonn,base,easy

%O 1,1

%A _Antti Karttunen_, Jun 04 2004