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A376868
a(n) = n! * 4^binomial(n, 2).
1
1, 1, 8, 384, 98304, 125829120, 773094113280, 22166154415964160, 2905362191609254379520, 1713652349303736855146004480, 4492236814558787941553941984051200, 51814968810690751870631528968553182003200, 2607932771310665560007967653747021825864997273600
OFFSET
0,3
COMMENTS
Conjecturally, the sum of the permanents of all nXn 0-1 matrices.
LINKS
Michael De Vlieger, Table of n, a(n) for n = 0..55
FORMULA
a(n) = A000142(n) * A053763(n).
MAPLE
a:= n-> n!*2^(n^2-n):
seq(a(n), n=0..14); # Alois P. Heinz, Oct 07 2024
MATHEMATICA
Array[#!*4^Binomial[#, 2] &, 12, 0] (* Michael De Vlieger, Oct 07 2024 *)
PROG
(PARI) a(n)=n!*4^binomial(n, 2)
(Python)
from sympy import factorial
def A376868(n): return factorial(n)<<n*(n-1) # Chai Wah Wu, Oct 07 2024
CROSSREFS
Sequence in context: A067624 A096204 A153836 * A151941 A085806 A042115
KEYWORD
nonn,easy
AUTHOR
STATUS
approved