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 A162619 #2 Mar 30 2012 17:34:01 %S A162619 1,1,2,2,3,4,3,4,5,6,6,7,8,9,10,7,8,9,10,11,12,10,11,12,13,14,15,16, %T A162619 11,12,13,14,15,16,17,18,14,15,16,17,18,19,20,21,22,19,20,21,22,23,24, %U A162619 25,26,27,28,20,21,22,23,24,25,26,27,28,29,30,25,26,27,28,29,30,31,32,33 %N A162619 Triangle read by rows in which row n lists n consecutive natural numbers A000027, starting with A014689(n) = A000040(n)-n. %C A162619 Note that the last term of the n-th row is A000040(n)-1 = A006093(n). %C A162619 See also A162618 and A162620. %e A162619 Triangle begins: %e A162619 .1; %e A162619 .1, 2; %e A162619 .2, 3, 4; %e A162619 .3, 4, 5, 6; %e A162619 .6, 7, 8, 9,10; %e A162619 .7, 8, 9,10,11,12; %e A162619 10,11,12,13,14,15,16; %e A162619 11,12,13,14,15,16,17,18; %e A162619 14,15,16,17,18,19,20,21,22; %e A162619 19,20,21,22,23,24,25,26,27,28; %e A162619 20,21,22,23,24,25,26,27,28,29,30; %Y A162619 Cf. A000040, A006093, A014689, A159797, A159798, A162611, A162618, A162620. %K A162619 easy,nonn,tabl %O A162619 1,3 %A A162619 _Omar E. Pol_, Jul 10 2009