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Triangle read by rows: (A004736 * A000012) + (A000012 * A004736) - A000012 as infinite lower triangular matrices.
1

%I #12 Jun 05 2023 05:22:31

%S 1,5,1,11,5,1,19,11,5,1,29,19,11,5,1,41,29,19,11,5,1,55,41,29,19,11,5,

%T 1,71,55,41,29,19,11,5,1,89,71,55,41,29,19,11,5,1,109,89,71,55,41,29,

%U 19,11,5,1,131,109,89,71,55,41,29,19,11,5,1,155,131,109,89,71,55,41,29,19,11,5,1

%N Triangle read by rows: (A004736 * A000012) + (A000012 * A004736) - A000012 as infinite lower triangular matrices.

%C Row sums = A084990 starting (1, 6, 17, 36, 65, 106, ...).

%F n-th row = n descending terms of A028387: (1, 5, 11, 19, 29, 41, 55, ...). By columns, each column = A028387: (1, 5, 11, 19, 29, ...).

%e First few rows of the triangle:

%e 1;

%e 5, 1;

%e 11, 5, 1;

%e 19, 11, 5, 1;

%e 29, 19, 11, 5, 1;

%e 41, 29, 19, 11, 5, 1;

%e 55, 41, 29, 19, 11, 5, 1;

%e ...

%Y Cf. A004736, A028387, A084990.

%K nonn,tabl

%O 1,2

%A _Gary W. Adamson_, Jul 14 2007

%E Sign in definition and a(41) corrected; more terms from _Georg Fischer_, Jun 05 2023