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 A337276 #9 Sep 10 2020 03:04:07 %S A337276 2,-1,3,-1,10,7,6,-1,11,15,14,35,18,19,31,-1,22,39,23,27,30,43,26,67, %T A337276 42,47,71,34,51,63,46,-1,75,55,50,79,54,38,83,59,58,62,87,91,90,95,99, %U A337276 94,66,70,86,103,106,98,74,82,119,102,107,123,110,111,118,-1,115,127,114,122,146,131,134 %N A337276 Index of appearance of 2*n in A336957, or -1 if 2*n never appears. %C A337276 It is a strong conjecture that 2*n appears in A336957 for all odd n, and it is known that 2^i does not appear for i>1. %e A337276 A336957(14) = 22, so a(11) = 14. %Y A337276 Cf. A336957, A337275. %K A337276 sign %O A337276 1,1 %A A337276 _N. J. A. Sloane_, Sep 09 2020