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!)
A245790 Number of preferential arrangements of n labeled elements when at least k=5 elements per rank are required. 5
1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 253, 925, 2509, 6007, 13443, 785643, 6114551, 31980469, 138704361, 539262713, 13685913105, 170996304653, 1442111683785, 9802624250281, 58233700998845, 939069565583991, 15109164547164171, 181402703206632211, 1758154702415920051 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,11

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..400

FORMULA

E.g.f.: 1/(2 + x - exp(x) + x^2/2! + x^3/3! + x^4/4!). - Vaclav Kotesovec, Aug 02 2014

a(n) ~ n! / ((1+r^4/4!) * r^(n+1)), where r = 2.376178375424367122... is the root of the equation 2 + r - exp(r) + r^2/2! + r^3/3! + r^4/4! = 0. - Vaclav Kotesovec, Aug 02 2014

MAPLE

a:= proc(n) option remember; `if`(n=0, 1,

       add(a(n-j)*binomial(n, j), j=5..n))

    end:

seq(a(n), n=0..30);

MATHEMATICA

CoefficientList[Series[1/(2 + x - E^x + x^2/2! + x^3/3! + x^4/4!), {x, 0, 30}], x]*Range[0, 30]! (* Vaclav Kotesovec, Aug 02 2014 *)

CROSSREFS

Cf. column k=5 of A245732.

Sequence in context: A158078 A157356 A203085 * A070193 A054737 A123013

Adjacent sequences:  A245787 A245788 A245789 * A245791 A245792 A245793

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Aug 01 2014

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 July 24 18:34 EDT 2021. Contains 346273 sequences. (Running on oeis4.)