A088128 Expansion of e.g.f.: cosh(x)/(1-x)^2.
1, 2, 7, 30, 157, 970, 6931, 56294, 512569, 5173074, 57330271, 692227822, 9045871957, 127205130650, 1915394962027, 30748771424310, 524265894691441, 9461374592096674, 180184121539899319, 3611206508019111614, 75978294135602723341, 1674381620327287502442
Offset: 0
Programs
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Mathematica
With[{nn=20},CoefficientList[Series[Cosh[x]/(1-x)^2,{x,0,nn}],x] Range[0,nn]!] (* Harvey P. Dale, Feb 02 2020 *)
Formula
a(n) = Sum_{k=0..floor(n/2)} binomial(n,2*k) * (n-2*k+1)!. - Ilya Gutkovskiy, Apr 10 2022
Extensions
Definition clarified by Harvey P. Dale, Feb 02 2020
Comments