cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A071595 Odd numbers k such that the number of 1's in binary representation of k equals omega(k), the number of distinct primes in the factorization of k.

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%I A071595 #11 Jan 11 2020 06:39:29
%S A071595 33,65,129,273,385,513,1025,1155,1281,2049,2065,2145,4097,4161,4641,
%T A071595 8193,8195,8211,8225,8265,8385,8449,9345,10241,16905,17409,21505,
%U A071595 24585,32775,32785,32835,32865,33033,33285,33345,33825,34881,36865,36993
%N A071595 Odd numbers k such that the number of 1's in binary representation of k equals omega(k), the number of distinct primes in the factorization of k.
%H A071595 Amiram Eldar, <a href="/A071595/b071595.txt">Table of n, a(n) for n = 1..1000</a>
%e A071595 129 = 10000001 in base 2 and 129 = 3*43 hence 129 is in the sequence.
%t A071595 Select[Range[1, 37000, 2], DigitCount[#, 2, 1] == PrimeNu[#] &] (* _Amiram Eldar_, Jan 11 2020*)
%o A071595 (PARI) for(n=1,80000,if(sum(i=1,length(binary(n)), component(binary(n),i))==-(-1)^n*omega(n),print1(n,",")))
%Y A071595 Cf. A071594, A071596.
%K A071595 base,easy,nonn
%O A071595 1,1
%A A071595 _Benoit Cloitre_, Jun 01 2002