G.f.: exp( Sum_{n>=1} [Sum_{k=0..2n} C(2n,k)^2*y^k]*x^n/n ) = Sum_{n>=0,k=0..2n} T(n,k)*x^n*y^k, as a triangle of coefficients T(n,k) read by rows.

A181145

G.f.: exp( Sum_{n>=1} [Sum_{k=0..2n} C(2n,k)^2*y^k]*x^n/n ) = Sum_{n>=0,k=0..2n} T(n,k)*x^n*y^k, as a triangle of coefficients T(n,k) read by rows.

Terms

    a(0) =1a(1) =1a(2) =4a(3) =1a(4) =1a(5) =12a(6) =27a(7) =12a(8) =1a(9) =1a(10) =24a(11) =134a(12) =236a(13) =134a(14) =24a(15) =1a(16) =1a(17) =40a(18) =410a(19) =1540a(20) =2380a(21) =1540a(22) =410a(23) =40a(24) =1a(25) =1a(26) =60a(27) =975a(28) =6260a(29) =18386

External references