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!)
A130636 a(n) = n*a(n-3) + a(n-4) for n >= 4. 0
0, 1, 0, 0, 4, 1, 0, 28, 12, 1, 280, 160, 24, 3641, 2520, 520, 58280, 46481, 11880, 1107840, 987900, 295961, 24384360, 23829540, 8090964, 609904961, 643952400, 242285568, 17085429872, 19284524561, 7912519440 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

LINKS

Table of n, a(n) for n=0..30.

FORMULA

a(n) = n*a(n-3) + a(n-4) for n >= 4. - Jianing Song, Oct 10 2018

MATHEMATICA

M[n_] := {{0, 0, n, 1}, {1, 0, 0, 0}, {0, 1, 0, 0}, {0, 0, 1, 0}};

v[0] = {0, 0, 0, 1};

v[n_] := v[n] = M[n].v[n - 1];

a = Table[v[n][[1]], {n, 0, 30}]

PROG

(PARI) a(n) = if(n<4, n==1, n*a(n-3) + a(n-4)) \\ Jianing Song, Oct 10 2018

CROSSREFS

Sequence in context: A069018 A156811 A246609 * A299354 A117414 A085639

Adjacent sequences:  A130633 A130634 A130635 * A130637 A130638 A130639

KEYWORD

nonn,easy

AUTHOR

Roger L. Bagula, Jun 19 2007

EXTENSIONS

Edited, new name, and offset corrected by Jianing Song, Oct 10 2018

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 January 25 00:44 EST 2022. Contains 350565 sequences. (Running on oeis4.)