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Triangle read by rows: A000012 * A126988 as infinite lower triangular matrices.
2

%I #12 May 29 2023 13:00:15

%S 1,3,1,6,1,1,10,3,1,1,15,3,1,1,1,21,6,3,1,1,1,28,6,3,1,1,1,1,36,10,3,

%T 3,1,1,1,1,45,10,6,3,1,1,1,1,1,55,15,6,3,3,1,1,1,1,1,66,15,6,3,3,1,1,

%U 1,1,1,1,78,21,10,6,3,3,1,1,1,1,1,1,91,21,10,6,3,3,1,1,1,1,1,1,1

%N Triangle read by rows: A000012 * A126988 as infinite lower triangular matrices.

%C Row sums = A024916: (1, 4, 8, 15, 21, 33, ...).

%F By columns, k=1,2,3,...; k repeated terms of the triangular series, (1, 3, 6, 10, ...) in the k-th column.

%e First few rows of the triangle:

%e 1;

%e 3, 1;

%e 6, 1, 1;

%e 10, 3, 1, 1;

%e 15, 3, 1, 1, 1;

%e 21, 6, 3, 1, 1, 1;

%e 28, 6, 3, 1, 1, 1, 1;

%e 36, 10, 3, 3, 1, 1, 1, 1;

%e 45, 10, 6, 3, 1, 1, 1, 1, 1;

%e ...

%Y Cf. A000012, A000217, A024916, A126988.

%K nonn,tabl

%O 1,2

%A _Gary W. Adamson_, Mar 04 2007

%E a(11) = 1 inserted and more terms from _Georg Fischer_, May 29 2023