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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A115140 O.g.f. inverse of Catalan A000108 o.g.f. 13
1, -1, -1, -2, -5, -14, -42, -132, -429, -1430, -4862, -16796, -58786, -208012, -742900, -2674440, -9694845, -35357670, -129644790, -477638700, -1767263190, -6564120420, -24466267020, -91482563640, -343059613650, -1289904147324, -4861946401452, -18367353072152 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

Seiichi Manyama, Table of n, a(n) for n = 0..1668

FORMULA

See A034807 and A115149 for comments.

For convolutions of this sequence see A115141-A115149.

O.g.f.: 1/c(x) = 1-x*c(x) with the o.g.f. c(x):=(1-sqrt(1-4*x))/(2*x) of A000108 (Catalan numbers).

a(0) = 1, a(n) = -C(n-1), n>=1, with C(n):=A000108(n) (Catalan).

G.f.: (1 + sqrt(1-4*x))/2=U(0) where U(k)=1 - x/U(k+1) ; (continued fraction, 1-step). - Sergei N. Gladkovskii, Oct 29 2012

G.f.: 1/G(0) where G(k) = 1 - x/(x - 1/G(k+1) ); (continued fraction). - Sergei N. Gladkovskii, Dec 12 2012

G.f.: G(0), where G(k)= 2*x*(2*k+1) + k + 1 - 2*x*(k+1)*(2*k+3)/G(k+1) ; (continued fraction). - Sergei N. Gladkovskii, Jul 14 2013

n*a(n) +2*(-2*n+3)*a(n-1)=0. a(n) = A002420(n)/2, n>0. - R. J. Mathar, Aug 09 2015

CROSSREFS

Sequence in context: A291825 A287974 * A120588 A168491 A000108 A057413

Adjacent sequences:  A115137 A115138 A115139 * A115141 A115142 A115143

KEYWORD

sign,easy

AUTHOR

Wolfdieter Lang, Jan 13 2006

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 17 05:27 EDT 2018. Contains 313810 sequences. (Running on oeis4.)