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 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

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