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.

A065878 Numbers which are not an integer multiple of their number of binary 1's.

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%I A065878 #21 Aug 05 2025 03:38:23
%S A065878 3,5,7,9,11,13,14,15,17,19,22,23,25,26,27,28,29,30,31,33,35,37,38,39,
%T A065878 41,43,44,45,46,47,49,50,51,52,53,54,56,57,58,59,61,62,63,65,67,70,71,
%U A065878 73,74,75,76,77,78,79,82,83,85,86,87,88,89,90,91,93,94,95,97,98,99,100
%N A065878 Numbers which are not an integer multiple of their number of binary 1's.
%H A065878 Amiram Eldar, <a href="/A065878/b065878.txt">Table of n, a(n) for n = 1..10000</a> (terms 1..1000 from Harry J. Smith)
%e A065878 5 is in the sequence since 5 = 101_2 and 5 is not a multiple of 1 + 0 + 1 = 2.
%t A065878 Select[Range[100],!IntegerQ[#/Total[IntegerDigits[#,2]]]&]  (* _Harvey P. Dale_, Apr 20 2011 *)
%o A065878 (PARI) isok(k) = k % hammingweight(k); \\ _Amiram Eldar_, Aug 04 2025
%Y A065878 Complement of A049445.
%Y A065878 The base-10 equivalent is A065877.
%Y A065878 Cf. A000120, A058898, A065413, A065879, A065880.
%K A065878 base,nonn,easy
%O A065878 1,1
%A A065878 _Henry Bottomley_, Nov 26 2001