login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A324959 a(n) is the coefficient of y^(n-1) in Product_{k=0..n-2} (n + (2*n + k)*y + n*y^2), for n >= 1. 2
1, 4, 60, 1584, 60460, 3029040, 188149822, 13957194496, 1204226253180, 118497226636800, 13098496404605964, 1607024046808249344, 216700840893719564902, 31857524157092264001280, 5071166437655033657264250, 868987068436739105218560000, 159492062728455524910446791332, 31215865935497559008870102593536, 6489956761227888786183691062551704, 1428394947783425181327275654594560000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(n) = A324958(n,n-1) for n >= 1.

LINKS

Vaclav Kotesovec, Table of n, a(n) for n = 1..300

FORMULA

a(n) ~ n! * c * 5^(5*n) / (2^(8*n) * n^2), where c = 0.04261749831824651172873387091554100360007169830546206828545398795767677148... - Vaclav Kotesovec, Oct 30 2019

MATHEMATICA

Table[If[n==1, 1, Coefficient[Expand[Product[(n + (2*n+k)*y + n*y^2), {k, 0, n-2}]], y^(n-1)]], {n, 1, 20}] (* Vaclav Kotesovec, Oct 30 2019 *)

PROG

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

for(n=1, 25, print1(a(n), ", "))

CROSSREFS

Cf. A324958.

Sequence in context: A013483 A013484 A013485 * A098630 A336637 A330069

Adjacent sequences:  A324956 A324957 A324958 * A324960 A324961 A324962

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Mar 20 2019

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 1 14:10 EST 2021. Contains 349430 sequences. (Running on oeis4.)