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 A280770 #9 Jan 17 2017 19:41:06 %S A280770 1,2,3,4,5,6,7,8,11,9,10,12,14,13,17,15,19,16,23,18,21,24,29,20,26,22, %T A280770 31,25,39,27,37,28,34,30,41,32,43,33,47,35,38,36,46,40,51,42,52,44,53, %U A280770 45,59,48,61,49,68,50,57,54,67,55,58,56,76,60,66,63,71,62,74,64,73,65,79,69,83,70,89,72,97 %N A280770 Even terms in A280864, divided by 2, in order of appearance. %C A280770 It is known (see A280864) that this is a permutation of the natural numbers. %H A280770 N. J. A. Sloane, <a href="/A280770/b280770.txt">Table of n, a(n) for n = 1..10486</a> %Y A280770 Cf. A280864, A280771. %K A280770 nonn %O A280770 1,2 %A A280770 _N. J. A. Sloane_, Jan 17 2017