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Unsigned row sums of triangle A104030, which is the matrix inverse of the triangle of pairwise sums of trinomial coefficients.
1

%I #7 Feb 03 2013 19:11:10

%S 1,3,13,83,781,10515,194125,4721363,146385805,5636169363,263831355085,

%T 14755901813843,971805538480141,74439152531508243,6561768848473177933,

%U 659527417026466047443,74976638559342869785741

%N Unsigned row sums of triangle A104030, which is the matrix inverse of the triangle of pairwise sums of trinomial coefficients.

%C Row sums of triangle A104030 forms negative Genocchi numbers (of first kind)(A001469).

%o (PARI) {a(n)=if(n<0,0,(sum(k=0,n,abs((matrix(n+2,n+2,m,j,if(m>=j, polcoeff((1+x+x^2)^(m-1)+O(x^(2*j)),2*j-2)+ polcoeff((1+x+x^2)^(m-1)+O(x^(2*j)),2*j-1))))^-1)[n+1,k+1])))}

%Y Cf. A104030.

%K nonn

%O 0,2

%A _Paul D. Hanna_, Feb 26 2005