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%I #7 Sep 08 2013 19:59:15
%S 1,1,1,3,1,1,5,5,1,1,11,9,7,1,1,21,25,13,9,1,1,43,53,43,17,11,1,1,85,
%T 125,97,65,21,13,1,1,171,273,255,153,91,25,15,1,1,341,609,597,441,221,
%U 121,29,17,1,1,683,1325,1443
%N Riordan array (1/(1-x-2x^2), x(1-x)/(1-x-2x^2)).
%C First column is A001045. Row sums are Pell numbers A000129(n+1). Diagonal sums are A125691.
%F G.f.: 1/(1-x-2x^2-xy(1-x)).
%F T(n,k) = T(n-1,k) + T(n-1,k-1) + 2*T(n-2,k) - T(n-2,k-1). - _Philippe Deléham_, Feb 24 2012
%e Triangle begins
%e 1,
%e 1, 1,
%e 3, 1, 1,
%e 5, 5, 1, 1,
%e 11, 9, 7, 1, 1,
%e 21, 25, 13, 9, 1, 1,
%e 43, 53, 43, 17, 11, 1, 1
%K easy,nonn,tabl
%O 0,4
%A _Paul Barry_, Nov 30 2006
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