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.
%I A080565 #7 Sep 04 2014 13:39:12 %S A080565 3,7,13,15,25,27,29,31,49,51,53,55,57,59,61,63,97,99,101,103,105,107, %T A080565 109,111,113,115,117,119,121,123,125,127,193,195,197,199,201,203,205, %U A080565 207,209,211,213,215,217,219,221,223,225,227,229,231,233 %N A080565 Binary expansion of n has form 11**...*1. %C A080565 If n>3 is in the sequence so are 2n-1 and 2n+1. %F A080565 a(n) = 2^floor(log[2](4*(n-1)))+2*n-1 for n>1, a(1)=3. - Antonio G. Astudillo (afg_astudillo(AT)hotmail.com), Feb 22 2003 %F A080565 Equals 2 * A004760(n) + 1. - _Ralf Stephan_, Sep 16 2003 %Y A080565 A004755 = union of A079946 and this sequence. %Y A080565 A diagonal of A246830. %K A080565 nonn %O A080565 1,1 %A A080565 _Benoit Cloitre_, Feb 22 2003