login
This site is supported by donations to The OEIS Foundation.

 

Logo

The submissions stack has been unacceptably high for several months now. Please voluntarily restrict your submissions and please help with the editing. (We don't want to have to impose further limits.)

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A143918 G.f. A(x) satisfies: A(x) = 1/(1-x)^2 + x^2*A'(x). 0
1, 2, 5, 14, 47, 194, 977, 5870, 41099, 328802, 2959229, 29592302, 325515335, 3906184034, 50780392457, 710925494414, 10663882416227, 170622118659650, 2900576017214069, 52210368309853262, 991996997887211999 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..20.

FORMULA

a(n) = 3*floor(e*(n-1)!) - 1, n>1. - Gary Detlefs, Jun 10 2010

EXAMPLE

G.f.: A(x) = 1 + 2*x + 5*x^2 + 14*x^3 + 47*x^4 + 194*x^5 + 977*x^6 +...

x^2*A'(x) = 2*x^2 + 10*x^3 + 42*x^4 + 188*x^5 + 970*x^6 + 5862*x^7 +...

MATHEMATICA

a=2; lst={}; Do[a=n+a*(n-2); AppendTo[lst, a], {n, 0, 3*4!}]; lst (* Vladimir Joseph Stephan Orlovsky, Mar 16 2010 *)

PROG

(PARI) {a(n)=local(A=1+x+x*O(x^n)); for(i=1, n, A=1/(1-x+x*O(x^n))^2+x^2*deriv(A)); polcoeff(A, n)}

CROSSREFS

Sequence in context: A096402 A007268 A109156 * A129867 A119841 A149905

Adjacent sequences:  A143915 A143916 A143917 * A143919 A143920 A143921

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Sep 05 2008

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified August 28 15:16 EDT 2015. Contains 261125 sequences.