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.

A235336 Numbers having evil number of 1's in their binary representation.

This page as a plain text file.
%I A235336 #26 Jul 24 2023 02:36:02
%S A235336 0,7,11,13,14,19,21,22,25,26,28,31,35,37,38,41,42,44,47,49,50,52,55,
%T A235336 56,59,61,62,63,67,69,70,73,74,76,79,81,82,84,87,88,91,93,94,95,97,98,
%U A235336 100,103,104,107,109,110,111,112,115,117,118,119,121,122,123,124,125,126,131
%N A235336 Numbers having evil number of 1's in their binary representation.
%C A235336 A000120(a(n)) is in A001969.
%C A235336 Except for 0, the first term in which the sequence differs from A075930 is the 27th: a(27) = 63.
%C A235336 Also a(27) = 63 is the first odd term that is not in A092246. - _Altug Alkan_, Mar 18 2018
%H A235336 Robert Israel, <a href="/A235336/b235336.txt">Table of n, a(n) for n = 0..10000</a>
%e A235336 7 in binary has 3 1's and since 3 is evil (i.e., belongs to A001969), then 7 is in the sequence.
%p A235336 filter:= n ->
%p A235336   convert(convert(convert(convert(n,base,2),`+`),base,2),`+`)::even:
%p A235336 select(filter, [$0..131]); # _Robert Israel_, Mar 18 2018
%t A235336 Select[Range[0, 150], EvenQ[DigitCount[DigitCount[#, 2, 1], 2, 1]] &] (* _Amiram Eldar_, Jul 24 2023 *)
%Y A235336 Cf. A000120, A001969, A075930, A092246.
%K A235336 nonn,base
%O A235336 0,2
%A A235336 _Vladimir Shevelev_, Jan 06 2014