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%I #5 Sep 08 2013 13:30:58
%S 1,2,2,3,7,3,4,16,16,4,5,30,51,30,5,6,50,126,126,50,6,7,77,266,393,
%T 266,77,7
%N Triangle T(n,k), 1<=k<=n :forms the odd-indexed trinomial coefficients (A027907).
%F Sum_{k, 1<=k<=n}T(n,k)=A003462(n)=(3^n-1)/2.
%e Triangle begins:
%e 1;
%e 2, 2;
%e 3, 7, 3;
%e 4, 16, 16, 4;
%e 5, 30, 51, 30, 5;
%e 6, 50, 126, 126, 50, 6;
%e 7, 77, 266, 393, 266, 77, 7;
%Y Cf. A056241.
%K nonn,tabl
%O 1,2
%A _Philippe Deléham_, Oct 30 2006
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