

A145225


T(n,k) is the number of odd permutations (of an nset) with exactly k fixed points.


0



0, 0, 0, 1, 0, 0, 0, 3, 0, 0, 6, 0, 6, 0, 0, 20, 30, 0, 10, 0, 0, 135, 120, 90, 0, 15, 0, 0, 924, 945, 420, 210, 0, 21, 0, 0, 7420, 7392, 3780, 1120, 420, 0, 28, 0, 0, 66744, 66780, 33264, 11340, 2520, 756, 0, 36, 0, 0
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OFFSET

0,8


LINKS

Table of n, a(n) for n=0..54.
Bashir Ali and A. Umar, Some combinatorial properties of the alternating group, Southeast Asian Bulletin Math. 32 (2008), 823830.


FORMULA

T(n,k) = C(n,k)*A145221(nk)
E.g.f.: (x^(k+2)*exp(x))/(2*(k!)*(1x)).


EXAMPLE

Triangle starts:
0;
0, 0;
1, 0, 0;
0, 3, 0, 0;
6, 0, 6, 0, 0;
20, 30, 0, 10, 0;
...


CROSSREFS

Row sum is A001710 for n > 1, sum of Row1=sum of Row2 = 0.
T(n, 0) is A145221, T(n, 1) is A145222, T(n, 2) is A145223.
Sequence in context: A062688 A067181 A321429 * A332442 A061480 A220692
Adjacent sequences: A145222 A145223 A145224 * A145226 A145227 A145228


KEYWORD

nonn,tabl


AUTHOR

Abdullahi Umar, Oct 10 2008


STATUS

approved



