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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A027784 a(n) = 11*(n+1)*binomial(n+2,11)/2. 1
55, 726, 5148, 26026, 105105, 360360, 1089088, 2975544, 7482618, 17551820, 38798760, 81477396, 163601438, 315762216, 588376800, 1062347000, 1864418985, 3188915730, 5327982660, 8713054350, 13970931975, 21998673840, 34062462720, 51926743440, 78021243300 (list; graph; refs; listen; history; text; internal format)
OFFSET

9,1

LINKS

T. D. Noe, Table of n, a(n) for n = 9..1000

Index entries for linear recurrences with constant coefficients, signature (13, -78, 286, -715, 1287, -1716, 1716, -1287, 715, -286, 78, -13, 1).

FORMULA

Number of 14-subsequences of [ 1, n ] with just 2 contiguous pairs; g.f. 11*(5+x)*x^9/(1-x)^13.

a(n) = C(n+1, 10)*C(n+2, 2). - Zerinvary Lajos, Apr 28 2005, corrected by R. J. Mathar, Mar 15 2016

MATHEMATICA

Table[11(n+1) Binomial[n+2, 11]/2, {n, 9, 40}] (* or *) LinearRecurrence[ {13, -78, 286, -715, 1287, -1716, 1716, -1287, 715, -286, 78, -13, 1}, {55, 726, 5148, 26026, 105105, 360360, 1089088, 2975544, 7482618, 17551820, 38798760, 81477396, 163601438}, 30] (* Harvey P. Dale, May 11 2013 *)

CROSSREFS

Sequence in context: A132155 A173377 A053138 * A297523 A221786 A241634

Adjacent sequences:  A027781 A027782 A027783 * A027785 A027786 A027787

KEYWORD

nonn,easy

AUTHOR

thi ngoc dinh (via R. K. Guy)

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 June 24 07:56 EDT 2021. Contains 345416 sequences. (Running on oeis4.)