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 A066123 #20 Dec 08 2024 14:15:36
%S A066123 11,13,23,29,39,43,53,55,57,59,69,79,81,87,91,109,117,121,133,143,151,
%T A066123 161,167,171,173,175,179,181,183,205,207,213,215,229,233,235,237,239,
%U A066123 241,243,245,247,261,265,277,287,289,303,311,321,327,337,343,347,349
%N A066123 Numbers that in base 2 need two 'Reverse and Add' steps to reach a palindrome.
%C A066123 The analog of A065207 in base 2. The number of steps starts at 0, so palindromes (cf. A006995) are excluded.
%C A066123 Numbers k such that A066057(k) = 2. - _Andrew Howroyd_, Dec 05 2024
%H A066123 Harry J. Smith, <a href="/A066123/b066123.txt">Table of n, a(n) for n = 1..1000</a>
%H A066123 <a href="/index/Res#RAA">Index entries for sequences related to Reverse and Add!</a>
%o A066123 (PARI) isok(n,s=2)={for(k=0, s, my(r=fromdigits(Vecrev(binary(n)),2)); if(r==n, return(k==s)); n += r); 0} \\ _Andrew Howroyd_, Dec 05 2024
%Y A066123 Cf. A006995, A065207, A066057, A066122.
%K A066123 base,nonn
%O A066123 1,1
%A A066123 _Klaus Brockhaus_, Dec 08 2001
%E A066123 Offset changed from 0 to 1 by _Harry J. Smith_, Feb 01 2010