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 A162618 #9 Dec 08 2015 08:57:32 %S A162618 1,1,2,1,2,3,2,3,4,5,3,4,5,6,7,6,7,8,9,10,11,7,8,9,10,11,12,13,10,11, %T A162618 12,13,14,15,16,17,11,12,13,14,15,16,17,18,19,14,15,16,17,18,19,20,21, %U A162618 22,23,19,20,21,22,23,24,25,26,27,28,29,20,21,22,23,24,25,26,27,28,29,30 %N A162618 Triangle read by rows in which row n lists n consecutive natural numbers A000027, starting with A008578(n-1) - n + 1. %C A162618 Note that the last term of the n-th row is the noncomposite number A008578(n-1). %e A162618 Contribution from _Omar E. Pol_, Jul 15 2009: (Start) %e A162618 Triangle begins: %e A162618 1; %e A162618 1, 2; %e A162618 1, 2, 3; %e A162618 2, 3, 4, 5; %e A162618 3, 4, 5, 6, 7; %e A162618 6, 7, 8, 9, 10, 11; %e A162618 7, 8, 9, 10, 11, 12, 13; %e A162618 10, 11, 12, 13, 14, 15, 16, 17; %e A162618 11, 12, 13, 14, 15, 16, 17, 18, 19; %e A162618 14, 15, 16, 17, 18, 19, 20, 21, 22, 23; %e A162618 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29; %e A162618 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31; %e A162618 (End) %Y A162618 Cf. A000040, A008578, A159797, A159798, A162611, A162619, A162620. %Y A162618 Cf. A162614, A162622. - _Omar E. Pol_, Jul 15 2009 %K A162618 easy,nonn,tabl %O A162618 1,3 %A A162618 _Omar E. Pol_, Jul 10 2009