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A124042 Number of permutations of n distinct letters (ABCD...) each of which appears thrice with two fixed points. 1
0, 9, 378, 84510, 38358540, 31234760055, 41467520432646, 83805898840005132, 244832935610272588920, 993012060508835944545045, 5413243051841698780829328690, 38622438042365626607874252846474 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..11.

EXAMPLE

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: A157567 A157593 A157602 * A297738 A225988 A012191

Adjacent sequences:  A124039 A124040 A124041 * A124043 A124044 A124045

KEYWORD

nonn

AUTHOR

Zerinvary Lajos, Nov 02 2006

STATUS

approved

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Last modified March 24 12:14 EDT 2019. Contains 321448 sequences. (Running on oeis4.)