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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A136592 Column 2 of triangle A136590. 4
1, 3, -13, -10, 394, -2016, -5076, 170064, -1155024, -5005440, 193724640, -1656720000, -10280355840, 465087087360, -4804977542400, -39012996556800, 2035558551398400, -24660231399014400, -248246498826547200, 14713557956794368000 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,2

LINKS

Table of n, a(n) for n=2..21.

FORMULA

E.g.f.: A(x) = log(1 + x + x^2)^2 / 2!.

EXAMPLE

E.g.f.: A(x) = 1*x^2/2! + 3*x^3/3! - 13*x^4/4! - 10*x^5/5! + 394*x^6/6! +...

MATHEMATICA

With[{nn=30}, Drop[CoefficientList[Series[Log[1+x+x^2]^2/2, {x, 0, nn}], x] Range[ 0, nn]!, 2]] (* Harvey P. Dale, Feb 28 2013 *)

PROG

(PARI) a(n)=(n+2)!*polcoeff(log(1+x+x^2 +x*O(x^(n+2)))^2/2!, n+2)

CROSSREFS

Cf. A136590, A136591, A136593, A136594.

Sequence in context: A273025 A273122 A071708 * A085416 A107802 A142351

Adjacent sequences:  A136589 A136590 A136591 * A136593 A136594 A136595

KEYWORD

sign

AUTHOR

Paul D. Hanna, Jan 10 2008

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified February 16 21:59 EST 2019. Contains 320200 sequences. (Running on oeis4.)