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.

A099248 Numbers such that length in binary representation and number of ones have a common divisor greater than 1.

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%I A099248 #25 Jul 16 2023 02:12:14
%S A099248 3,7,9,10,12,15,31,33,34,35,36,37,38,39,40,41,42,43,44,45,46,48,49,50,
%T A099248 51,52,53,54,56,57,58,60,63,127,129,130,132,135,136,139,141,142,144,
%U A099248 147,149,150,153,154,156,159,160,163,165,166,169,170,172,175,177,178,180
%N A099248 Numbers such that length in binary representation and number of ones have a common divisor greater than 1.
%H A099248 Reinhard Zumkeller, <a href="/A099248/b099248.txt">Table of n, a(n) for n = 1..10000</a> (first 1810 terms from Diana Mecum)
%H A099248 <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a>.
%F A099248 A099244(a(n)) > 1.
%t A099248 Select[Range[200], !CoprimeQ[BitLength[#], DigitCount[#, 2, 1]] &] (* _Amiram Eldar_, Jul 16 2023 *)
%o A099248 (Haskell)
%o A099248 a099248 n = a099248_list !! (n-1)
%o A099248 a099248_list = filter ((> 1) . a099244) [1..]
%o A099248 -- _Reinhard Zumkeller_, Oct 10 2013
%Y A099248 Complement of A099247.
%Y A099248 Cf. A000120, A007088, A070939, A099244.
%K A099248 nonn,base
%O A099248 1,1
%A A099248 _Reinhard Zumkeller_, Oct 08 2004
%E A099248 Corrected by _Leroy Quet_, Sep 04 2008
%E A099248 a(34) and beyond from _Diana L. Mecum_, Jan 04 2009