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 A115302 #7 Oct 14 2012 09:53:22 %S A115302 1,4,2,7,5,3,10,8,6,13,11,9,16,14,12,19,17,15,22,20,18,25,23,21,28,26, %T A115302 24,31,29,27,34,32,30,37,35,33,40,38,36,43,41,39,46,44,42,49,47,45,52, %U A115302 50,48,55,53,51,58,56,54,61,59,57,64,62,60 %N A115302 Permutation of natural numbers generated by 3-rowed array shown below. %C A115302 1 4 7 10 13 16 19 22 25...a(n)=3n+1 => A016777 %C A115302 2 5 8 11 14 17 20 23 26...a(n)=3n+2 => A016789 %C A115302 3 6 9 12 15 18 21 24 27...a(n)=3n => A008585 %C A115302 Reversing the direction of the diagonals gives A143097. - _Jeremy Gardiner_, Oct 14 2012. %D A115302 M. Cerasoli, F. Eugeni and M. Protasi, Elementi di Matematica Discreta, Bologna 1988 %D A115302 Emanuele Munarini and Norma Zagaglia Salvi, Matematica Discreta,UTET, CittaStudiEdizioni, Milano 1997 %F A115302 For n > 1, a(n+5) = a(n) + 6, iff a(n+5)<a(n): a(n+3k) = a(n) + 3k with k >=1. %Y A115302 Cf. A088520, A090243, A090298, A143097. %K A115302 easy,nonn %O A115302 1,2 %A A115302 _Giovanni Teofilatto_, Mar 05 2006