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 A090243 #6 Mar 30 2012 18:39:59 %S A090243 1,7,2,11,6,3,13,10,5,4,19,14,9,8,23,18,15,12,25,22,17,16,31,26,21,20, %T A090243 35,30,27,24,37,34,29,28,43,38,33,32,47,42,39,36,49,46,41,40,55,50,45, %U A090243 44,59,54,51,48,61,58,53,52,67,62,57,56,71,66,63,60,73,70,65,64,79,74 %N A090243 Permutation of natural numbers generated by 4-rowed array shown below. %C A090243 1 7 11 13 19 23 25 31 35 37 43 47 ... %C A090243 2 6 10 14 18 22 26 30 34 38 42 46 ... %C A090243 3 5 9 15 17 21 27 29 33 39 41 45 ... %C A090243 4 8 12 16 20 24 28 32 36 40 44 48 ... %D A090243 M. Cerasoli, F. Eugeni and M. Protasi, Elementi di Matematica Discreta, Bologna 1988 %D A090243 Emanuele Munarini and Norma Zagaglia Salvi, Matematica Discreta,UTET, CittaStudiEdizioni, Milano 1997 %Y A090243 Cf. A088520, A090298, A092260, A113807. %K A090243 easy,nonn %O A090243 1,2 %A A090243 _Giovanni Teofilatto_, Jan 24 2004 %E A090243 Corrected and extended by _Ray Chandler_, Jan 30 2004