a(n) = (3*n)!/(2*n)! * Sum_{k=1..n} 1/(2*n+k).

A384136

a(n) = (3*n)!/(2*n)! * Sum_{k=1..n} 1/(2*n+k).

Terms

    a(0) =1a(1) =11a(2) =191a(3) =4578a(4) =140274a(5) =5238132a(6) =230784840a(7) =11720201616a(8) =674092013040

External references