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A372199
a(n) = n! * F(n) * H(n), where F(n) is the n-th Fibonacci number and H(n) the n-th harmonic number.
1
1, 3, 22, 150, 1370, 14112, 169884, 2301264, 34903584, 584575200, 10728401760, 214047774720, 4614042856320, 106866549054720, 2646889430976000, 69814736722483200, 1953778728154982400, 57822137143219814400, 1804373878844546150400, 59213693468692224000000
OFFSET
1,2
FORMULA
E.g.f.: (5*x*log(-x^2 - x + 1) - sqrt(5)*(x - 2)*(log(2 - (sqrt(5) + 1)*x) -log((sqrt(5) - 1)*x + 2))) / (10*x*(x^2 + x - 1)).
a(n) = n! * A000045(n) * A001008(n) / A002805(n).
a(n) = A000045(n) * A000254(n) / A002805(n). - R. J. Mathar, Apr 24 2024
D-finite with recurrence 5*a(n) +5*(-2*n+1)*a(n-1) +(-5*n^2+10*n+1)*a(n-2) +(10*n^3-45*n^2+58*n-14)*a(n-3) +(5*n^4-40*n^3+109*n^2-108*n+16)*a(n-4) +2*(n-4)^3*a(n-5) +(n-4)^2*(n-5)^2*a(n-6)=0. - R. J. Mathar, Apr 24 2024
MAPLE
H := proc(n)
add(1/i, i=1..n) ;
end proc:
A372199 := proc(n)
n!*A000045(n)*H(n) ;
end proc:
seq(A372199(n), n=1..70) ; # R. J. Mathar, Apr 24 2024
MATHEMATICA
a[n_] := n! Fibonacci[n] HarmonicNumber[n]; Array[a, 20] (* Stefano Spezia, Apr 22 2024 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Kruchinin, Apr 21 2024
STATUS
approved