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a(n) = sum of the n-th power of the trinomial coefficients in row n of triangle A027907.
1

%I #2 Mar 30 2012 18:37:20

%S 1,3,19,831,281907,764206503,16955359883149,3120135986465328015,

%T 4819828380706011142058787,63004580363300194268932114354503,

%U 7017256966823394610075464951176481843849

%N a(n) = sum of the n-th power of the trinomial coefficients in row n of triangle A027907.

%F Ignoring initial term, equals the logarithmic derivative of A168590.

%o (PARI) a(n)=sum(k=0,2*n,polcoeff((1+x+x^2)^n,k)^n)

%Y Cf. A168590, A027907.

%K nonn

%O 0,2

%A _Paul D. Hanna_, Dec 01 2009