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A098558 Expansion of e.g.f. (1+x)/(1-x). 14
1, 2, 4, 12, 48, 240, 1440, 10080, 80640, 725760, 7257600, 79833600, 958003200, 12454041600, 174356582400, 2615348736000, 41845579776000, 711374856192000, 12804747411456000, 243290200817664000, 4865804016353280000, 102181884343418880000, 2248001455555215360000 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Essentially the same as A052849: a(0)=0 and a(n) = A052849(n) for n>=1.

Row sums of triangle A008518.

Equals row sums (unsigned) of triangle A158471. - Gary W. Adamson, Mar 20 2009

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..445

FORMULA

a(n) = 2*n! - 0^n = 2*n! - !n.

G.f.: U(0) where U(k) = 1 + x*(k+1)/(1 - 1/(1 + 1/U(k+1))); (continued fraction, 3-step). - Sergei N. Gladkovskii, Nov 16 2012

MAPLE

seq(factorial(n)*coeff(series((1+x)/(1-x), x=0, 48), x, n), n=0..22); # Paolo P. Lava, Jan 09 2019

MATHEMATICA

Join[{1}, Table[2*n!, {n, 1, 30}]] (* or *) With[{nmax = 50}, CoefficientList[Series[(1 + x)/(1 - x), {x, 0, nmax}], x]*Range[0, nmax]!] (* G. C. Greubel, Jan 17 2018 *)

PROG

(PARI) for(n=0, 30, print1(if(n==0, 1, 2*n!), ", ")) \\ G. C. Greubel, Jan 17 2018

(MAGMA) [1] cat [Factorial(n): n in [1..30]]; // G. C. Greubel, Jan 17 2018

CROSSREFS

Cf. A000142, A000007.

Cf. A158471. - Gary W. Adamson, Mar 20 2009

Sequence in context: A013172 A321009 A052849 * A152827 A030813 A126772

Adjacent sequences:  A098555 A098556 A098557 * A098559 A098560 A098561

KEYWORD

easy,nonn

AUTHOR

Paul Barry, Sep 14 2004

STATUS

approved

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Last modified July 23 01:51 EDT 2019. Contains 325228 sequences. (Running on oeis4.)