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Eigentriangle, row sums = A000081 starting (1, 2, 4, 9, 20, 48, 115, ...).
2

%I #4 Feb 08 2022 23:29:31

%S 1,1,1,1,1,2,2,1,2,4,3,2,2,4,9,8,3,4,4,9,20,16,8,6,8,9,20,48,41,16,16,

%T 12,18,20,48,115,98,41,32,32,27,40,115,286,250,98,82,64,72,60,96,115,

%U 286,719

%N Eigentriangle, row sums = A000081 starting (1, 2, 4, 9, 20, 48, 115, ...).

%C Row sums = A000081 starting with offset 2: (1, 2, 4, 9, 20, 48, 115, ...).

%C Right border = (1, 1, 2, 4, 9, 20, 48, ...).

%C Left border = A051573: (1, 1, 1, 2, 3, 8, 16, 41, ...).

%C Sum of n-th row terms = rightmost term of next row.

%F Eigentriangle by rows, termwise products of A000081 starting with offset 2: (1, 2, 4, 9, 20, 48, ...) and row terms of an A051573 decrescendo triangle: (1; 1,1; 1,1,1; 2,1,1,1; 3,2,1,1,1; ...) where A051573 = (1, 1, 1, 2, 3, 8, 16, 41, ...).

%e First few rows of the triangle:

%e 1;

%e 1, 1;

%e 1, 1, 2;

%e 2, 1, 2, 4;

%e 3, 2, 2, 4, 9;

%e 8, 3, 4, 4, 9, 20;

%e 16, 8, 6, 8, 9, 20, 48;

%e 41, 16, 16, 12, 18, 20, 48, 115;

%e 98, 41, 32, 32, 27, 40, 48, 115, 286;

%e ...

%e Row 4 = (2, 1, 2, 4) = termwise products of (2, 1, 1, 1) and (1, 1, 2, 4).

%K eigen,nonn,tabl

%O 1,6

%A _Gary W. Adamson_, Sep 27 2008