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 A250471 #10 Dec 13 2014 00:40:32 %S A250471 1,2,3,5,4,8,6,11,13,14,7,17,9,20,18,23,10,26,12,29,28,32,15,35,25,38, %T A250471 33,41,16,44,19,47,43,50,39,53,21,56,48,59,22,62,24,65,58,68,27,71,61, %U A250471 74,63,77,30,80,46,83,73,86,31,89,34,92,78,95,60,98,36,101,88,104,37,107,40,110,93,113,72,116,42,119,103,122,45,125,67,128,108,131,49 %N A250471 Permutation of natural numbers: a(n) = (A250469(n) + 1) / 2. %H A250471 Antti Karttunen, <a href="/A250471/b250471.txt">Table of n, a(n) for n = 1..5002</a> %H A250471 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %F A250471 a(n) = (A250469(n) + 1) / 2. %o A250471 (Scheme) (define (A250471 n) (/ (+ 1 (A250469 n)) 2)) %Y A250471 Inverse: A250472. %Y A250471 Cf. A048673, A250469. %K A250471 nonn %O A250471 1,2 %A A250471 _Antti Karttunen_, Dec 06 2014