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

 

Logo

Annual Appeal: Please make a donation (tax deductible in USA) to keep the OEIS running. Over 5000 articles have referenced us, often saying "we discovered this result with the help of the OEIS".

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A124007 Number of permutations of n distinct letters (ABCD...) each of which appears thrice with n-3 fixed points. 1
0, 0, 54, 216, 540, 1080, 1890, 3024, 4536, 6480, 8910, 11880, 15444, 19656, 24570 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..14.

EXAMPLE

Maple produces the following triangle - the entries in quotes give the sequence:

1

"0", 0, 0, 1

1, 0, 9, "0", 9, 0, 1

56, 216, 378, 435, 324, 189, "54", 27, 0, 1

13833, 49464, 84510, 90944, 69039, 38448, 16476, 5184, 1431, "216", 54, 0, 1

6699824, 23123880, 38358540, 40563765, 30573900, 17399178, 7723640, 2729295, 776520, 180100, 33372, 5355, "540", 90, 0, 1

etc...

MAPLE

p := (x, k)->k!^2*sum(x^j/((k-j)!^2*j!), j=0..k); R := (x, n, k)->p(x, k)^n; f := (t, n, k)->sum(coeff(R(x, n, k), x, j)*(t-1)^j*(n*k-j)!, j=0..n*k); for n from 0 to 6 do seq(coeff(f(t, n, 3), t, m)/3!^n, m=0..3*n); od;

CROSSREFS

Cf. A059058, A027468, A059073, A000459.

Sequence in context: A157428 A068380 A187299 * A221867 A248209 A245830

Adjacent sequences:  A124004 A124005 A124006 * A124008 A124009 A124010

KEYWORD

nonn

AUTHOR

Zerinvary Lajos, Nov 01 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 December 6 12:54 EST 2016. Contains 278781 sequences.