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%I #7 Dec 26 2023 10:19:08
%S 1,1,1,1,1,1,3,2,1,1,3,2,1,1,1,7,5,3,2,1,1,7,5,3,2,1,1,1,17,12,7,5,3,
%T 2,1,1,17,12,7,5,3,2,1,1,1,41,29,17,12,7,5,3,2,1,1,41,29,17,12,7,5,3,
%U 2,1,1,1
%N Generalized (conditional) Riordan array with k-th column generated by x^k * (1 + x - x^2 + x^3)/(1 - 2x^2 - x^4) if k mod 2 = 0, x^k * (1+x)/(1 - 2x^2 - x^4) otherwise.
%C An eigentriangle of A181656. Even columns are essentially A001333 doubled. Odd columns are doubled Pell numbers (A000129).
%C Row sums are A181658.
%e Triangle begins
%e 1;
%e 1, 1;
%e 1, 1, 1;
%e 3, 2, 1, 1;
%e 3, 2, 1, 1, 1;
%e 7, 5, 3, 2, 1, 1;
%e 7, 5, 3, 2, 1, 1, 1;
%e 17, 12, 7, 5, 3, 2, 1, 1;
%e 17, 12, 7, 5, 3, 2, 1, 1, 1;
%e 41, 29, 17, 12, 7, 5, 3, 2, 1, 1;
%e 41, 29, 17, 12, 7, 5, 3, 2, 1, 1, 1;
%K easy,nonn,tabl
%O 0,7
%A _Paul Barry_, Nov 03 2010
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