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A095315
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Primes in whose binary expansion the number of 1 bits is <= 2 + number of 0 bits.
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5
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2, 3, 5, 11, 13, 17, 19, 37, 41, 43, 53, 67, 71, 73, 83, 89, 97, 101, 113, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 193, 197, 199, 211, 227, 229, 233, 241, 257, 263, 269, 271, 277, 281, 283, 293, 307, 313, 331, 337, 353, 389, 397
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OFFSET
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1,1
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LINKS
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EXAMPLE
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13 is in the sequence because 13 = 1101_2. '1101' has three 1's and one 0. 3 = 2 + 1. - Indranil Ghosh, Feb 07 2017
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MATHEMATICA
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Select[Prime[Range[100]], DigitCount[#, 2, 1]<3+DigitCount[#, 2, 0]&] (* Harvey P. Dale, Aug 12 2016 *)
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PROG
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(PARI) B(x) = { nB = floor(log(x)/log(2)); b1 = 0; b0 = 0;
for(i = 0, nB, if(bittest(x, i), b1++; , b0++; ); );
if(b1 <= (2+b0), return(1); , return(0); ); };
forprime(x = 2, 397, if(B(x), print1(x, ", "); ); );
(Python)
i=j=1
while j<=250:
if isprime(i) and bin(i)[2:].count("1")<=2+bin(i)[2:].count("0"):
print(str(j)+" "+str(i))
j+=1
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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