login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo

Please make a donation to keep the OEIS running. We are now in our 56th year. In the past year we added 10000 new sequences and reached almost 9000 citations (which often say "discovered thanks to the OEIS").
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A009591 Expansion of e.g.f. sinh(sin(x)) * sin(x) (even powers only). 2
0, 2, -4, -42, 888, -8086, -115468, 8863806, -275344656, 2488177106, 369676840940, -34139482063962, 1691837365047912, -16526563632072646, -7669129653528552220, 1088114395890103645710, -87525176659638470236704 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..250

FORMULA

a(n) = 2*Sum_{j=1..n} 4^(n-j)/(2*j-1)!*Sum_{i=0..j-1} (i-j)^(2*n)* binomial(2*j,i)*(-1)^(n+j-i). - Vladimir Kruchinin, Jun 09 2011

MATHEMATICA

With[{nn=40}, Take[CoefficientList[Series[Sinh[Sin[x]]Sin[x], {x, 0, nn}], x]Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Dec 08 2012 *)

PROG

(Maxima)

a(n):=2*sum(4^(n-j)/(2*j-1)!*sum((i-j)^(2*n)*binomial(2*j, i)*(-1)^(n+j-i), i, 0, j-1), j, 1, n); /* Vladimir Kruchinin, Jun 09 2011 */

(PARI) x='x+O('x^40); v=Vec(serlaplace(sinh(sin(x))*sin(x))); concat([0], vector(#v\2 , n, v[2*n-1])) \\ G. C. Greubel, Jan 30 2018

CROSSREFS

Sequence in context: A009547 A215921 A009811 * A009717 A018317 A059794

Adjacent sequences:  A009588 A009589 A009590 * A009592 A009593 A009594

KEYWORD

sign

AUTHOR

R. H. Hardin

EXTENSIONS

Extended with signs by Olivier Gérard, Mar 15 1997

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 December 1 09:28 EST 2020. Contains 338833 sequences. (Running on oeis4.)