OFFSET
0,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..360
FORMULA
a(n) = 2*4^n*n! - 0^n.
a(n+1) = 8*A034177(n).
a(n) - 4*n*a(n-1) = 0. - R. J. Mathar, Dec 21 2014
Sum_{n>=0} 1/a(n) = (exp(1/4)+1)/2. - Amiram Eldar, Feb 02 2023
MATHEMATICA
s=2; lst={1}; Do[s+=n*s+s; AppendTo[lst, s], {n, 2, 5!, 4}]; lst (* Vladimir Joseph Stephan Orlovsky, Nov 08 2008 *)
With[{nn=20}, CoefficientList[Series[(1+4x)/(1-4x), {x, 0, nn}], x] Range[0, nn]!] (* or *) Join[{1}, Table[2*4^n n!, {n, 20}]] (* Harvey P. Dale, Jan 16 2012 *)
PROG
(PARI) for(n=0, 30, print1(if(n==0, 1, 2^(2*n+1)*n!), ", ")) \\ G. C. Greubel, Jan 17 2018
(Magma) [1] cat [2^(2*n+1)*Factorial(n): n in [2..30]]; // G. C. Greubel, Jan 17 2018
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Sep 14 2004
STATUS
approved