%I #8 Jun 13 2014 11:50:37
%S 1,0,3,0,0,6,0,0,0,10,0,0,0,0,15,0,0,0,0,0,21,0,0,0,0,0,0,28,0,0,0,0,
%T 0,0,0,36,0,0,0,0,0,0,0,0,45,0,0,0,0,0,0,0,0,0,55
%N Triangle read by rows: row n consists of n-1 zeros followed by n(n+1)/2.
%e First few rows of the triangle are:
%e 1;
%e 0, 3;
%e 0, 0, 6;
%e 0, 0, 0, 10;
%e 0, 0, 0, 0, 15;
%e ...
%t Flatten[Table[{(n(n+1))/2,Table[0,{n}]},{n,10}]] (* _Harvey P. Dale_, Apr 03 2011 *)
%Y Cf. A127648, A000217, A127774.
%K nonn,easy,tabl
%O 1,3
%A _Gary W. Adamson_, Jan 28 2007
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