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A054780 Number of n-covers of a labeled n-set. 2
1, 1, 3, 32, 1225, 155106, 63602770, 85538516963, 386246934638991, 6001601072676524540, 327951891446717800997416, 64149416776011080449232990868, 45546527789182522411309599498741023 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..12.

FORMULA

a(n) = Sum_{k=0..n} (-1)^k*C(n, k)*C(2^(n-k)-1, n).

Also a(n) = (1/n!)*Sum_{k=0..n} Stirling1(n+1, k+1)*(2^k-1)^n.

G.f.: Sum_{n>=0} log(1+(2^n-1)*x)^n/((1+(2^n-1)*x)*n!). - Paul Hanna and Vladeta Jovovic, Jan 16 2008

CROSSREFS

Cf. A048291.

Main diagonal of A055154.

Sequence in context: A278069 A129431 A202806 * A203323 A222683 A134474

Adjacent sequences:  A054777 A054778 A054779 * A054781 A054782 A054783

KEYWORD

easy,nonn

AUTHOR

Vladeta Jovovic, May 21 2000

STATUS

approved

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Last modified December 2 17:22 EST 2016. Contains 278682 sequences.