A324957 a(n) is the coefficient of y^(n-1) in Product_{k=0..n-2} (n + (n + k)*y + n*y^2), for n >= 1.

1, 2, 30, 600, 17980, 701280, 33904822, 1956209024, 131229583596, 10037690006400, 862338700678884, 82216457762199552, 8614684257283258102, 984021646462806049280, 121700458370370286320750, 16202120194768984283381760, 2310243113824870018738497732, 351271199659878407029587277824, 56734597035765569017356665543968, 9700307843128908988513920450560000

Offset

1,2

Comments

a(n) = A324956(n,n-1) for n >= 1.

Links

Table of n, a(n) for n=1..20.

Prog

(PARI) {a(n) = polcoeff( prod(k=0, n-2, n + (n+k)*y + n*y^2 +y*O(y^n)), n-1, y)}
for(n=1, 25, print1(a(n), ", "))

Crossrefs

Cf. A324956.

Sequence in context: A020547 A208881 A297490 * A282733 A363113 A160694

Adjacent sequences: A324954 A324955 A324956 * A324958 A324959 A324960

Keyword

nonn

Author

Paul D. Hanna, Mar 21 2019

Status

approved