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%I #11 Aug 12 2015 02:13:18
%S 1,1,2,3,1,2,3,4,5,6,1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,11,12,
%T 13,14,15,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,1,2,3,
%U 4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,1,2,3
%N Sequence obtained by reading the triangles shown below by rows.
%C It appears that this is also a triangle read by rows in which row n lists the first A000217(n) positive integers, n >= 1 (see example, second part). - _Omar E. Pol_, May 29 2012
%e 1
%e 1
%e 2 3
%e 1
%e 2 3
%e 4 5 6
%e 1
%e 2 3
%e 4 5 6
%e 7 8 9 10
%e 1
%e 2 3
%e 4 5 6
%e 7 8 9 10
%e 11 12 13 14 15
%e From _Omar E. Pol_, May 29 2012: (Start)
%e Written as an irregular triangle the sequence begins:
%e 1;
%e 1, 2, 3;
%e 1, 2, 3, 4, 5, 6;
%e 1, 2, 3, 4, 5, 6, 7, 8, 9, 10;
%e 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15;
%e Row n has length A000217(n). (End)
%p A000217 := proc(n) n*(n+1)/2 ; end : for t from 1 to 10 do for i from 1 to A000217(t) do printf("%d, ",i) ; od ; od ; # _R. J. Mathar_, May 18 2007
%Y See A115215 for another version.
%K nonn,tabf,easy
%O 1,3
%A _Colm Mulcahy_, Dec 05 2006
%E More terms from _R. J. Mathar_, May 18 2007
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