cp's OEIS Frontend

A095286 Primes in whose binary expansion the number of 1 bits is > 1 + number of 0 bits.

%I A095286 #22 Jun 05 2020 04:05:44
%S A095286 3,7,11,13,23,29,31,43,47,53,59,61,79,103,107,109,127,151,157,167,173,
%T A095286 179,181,191,199,211,223,227,229,233,239,241,251,311,317,347,349,359,
%U A095286 367,373,379,383,431,439,443,461,463,467,479,487,491,499
%N A095286 Primes in whose binary expansion the number of 1 bits is > 1 + number of 0 bits.
%H A095286 Indranil Ghosh, <a href="/A095286/b095286.txt">Table of n, a(n) for n = 1..25000</a>
%H A095286 A. Karttunen and J. Moyer: <a href="/A095062/a095062.c.txt">C-program for computing the initial terms of this sequence</a>
%e A095286 13 is in the sequence because 13 is prime and 13 = 1101_2. '1101' has three 1's and one 0. 3 > 1 + 1. - _Indranil Ghosh_, Feb 07 2017
%o A095286 (PARI)B(x) = {nB = floor(log(x)/log(2)); b1 = 0; b0 = 0;
%o A095286 for(i = 0, nB, if(bittest(x,i), b1++;, b0++;); );
%o A095286 if(b1 > (b0+1), return(1);, return(0);); };
%o A095286 forprime(x = 3, 499, if(B(x), print1(x, ", "); ); );
%o A095286 \\ _Washington Bomfim_, Jan 11 2011
%o A095286 (Python)
%o A095286 from sympy import isprime
%o A095286 i = 1
%o A095286 j = 1
%o A095286 while j <= 2000:
%o A095286     bi = bin(i)[2:]
%o A095286     if isprime(i) and bi.count("1") > 1 + bi.count("0"):
%o A095286         print(str(j) + " " + str(i))
%o A095286         j += 1
%o A095286     i += 1 # _Indranil Ghosh_, Feb 07 2017
%Y A095286 Complement of A095287 in A000040. Subset of A095070. Subset: A095314. Cf. also A095296.
%K A095286 nonn,easy,base
%O A095286 1,1
%A A095286 _Antti Karttunen_, Jun 04 2004