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Triangle read by rows: A127701 * A002260 as infinite lower triangular matrices.
2

%I #13 Jun 05 2023 04:28:30

%S 1,3,4,4,8,9,5,10,15,16,6,12,18,24,25,7,14,21,28,35,36,8,16,24,32,40,

%T 48,49,9,18,27,36,45,54,63,64,10,20,30,40,50,60,70,80,81,11,22,33,44,

%U 55,66,77,88,99,100,12,24,36,48,60,72,84,96,108,120,121,13,26,39,52,65,78,91,104,117,130,143,144

%N Triangle read by rows: A127701 * A002260 as infinite lower triangular matrices.

%F Row sums = A127736: (1, 7, 21, 46, 85, 141, ...).

%F T(n,n) = n^2. T(n,k) = k*(n+1), 1<=k<n. - _R. J. Mathar_, Jul 21 2009

%e First few rows of the triangle are:

%e 1;

%e 3, 4;

%e 4, 8, 9;

%e 5, 10, 15, 16;

%e 6, 12, 18, 24, 25;

%e ...

%Y Cf. A002260, A127701, A127736.

%K nonn,tabl

%O 1,2

%A _Gary W. Adamson_, Jan 26 2007

%E A-number of left factor in the definition corrected by _R. J. Mathar_, Jul 21 2009

%E a(19) corrected and more terms from _Georg Fischer_, Jun 05 2023