login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A151646 Number of permutations of 4 indistinguishable copies of 1..n with exactly 8 adjacent element pairs in decreasing order. 2
0, 0, 1, 4961755, 93200908410, 342907451401150, 580563155365559991, 636819836268006188325, 536414785137072299859000, 381545916738691833553696960, 242640958318176281706165559005, 143034343946525950106468425526767, 80029528286823033581035280235294534 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Andrew Howroyd, Table of n, a(n) for n = 1..200

G. C. Greubel, Generating functions and recurrence

FORMULA

From G. C. Greubel, Sep 12 2022: (Start)

a(n) = Sum_{j=0..8} (-1)^j*binomial(4*n+1, j)*binomial(12-j, 4)^n.

G.f., e.g.f., and recurrence are in the file "Generating functions and recurrence". (End)

MATHEMATICA

Table[Sum[(-1)^j*Binomial[4*n+1, j]*Binomial[12-j, 4]^n, {j, 0, 8}], {n, 30}] (* G. C. Greubel, Sep 12 2022 *)

PROG

(Magma) [(&+[(-1)^j*Binomial(4*n+1, j)*Binomial(12-j, 4)^n: j in [0..8]]): n in [1..30]]; // G. C. Greubel, Sep 12 2022

(SageMath)

def A151646(n): return sum((-1)^j*binomial(4*n+1, j)*binomial(12-j, 4)^n for j in (0..8))

[A151646(n) for n in (1..30)] # G. C. Greubel, Sep 12 2022

CROSSREFS

Column k=8 of A236463.

Sequence in context: A244266 A222976 A157804 * A210318 A227155 A106785

Adjacent sequences:  A151643 A151644 A151645 * A151647 A151648 A151649

KEYWORD

nonn

AUTHOR

R. H. Hardin, May 29 2009

EXTENSIONS

Terms a(8) and beyond from Andrew Howroyd, May 06 2020

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 3 06:21 EDT 2022. Contains 357230 sequences. (Running on oeis4.)