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A056990 Number of nonsingular n X n (-1,1)-matrices. 6
1, 2, 8, 192, 22272, 11550720, 25629327360, 236229525504000, 8858686914082897920, 1331751782100764385607680 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
LINKS
Eric Weisstein's World of Mathematics, Nonsingular Matrix.
FORMULA
a(n) = 2^(2*n-1) * A055165(n-1) for n>=1.
CROSSREFS
Sequence in context: A009505 A305737 A028368 * A234637 A234632 A070235
KEYWORD
nonn,nice
AUTHOR
EXTENSIONS
a(5) from Winston C. Yang (winston(AT)cs.wisc.edu), Aug 26 2000
a(6)-a(8) computed from A055165 by David desJardins, Apr 22 2001
a(9) from Max Alekseyev, computed from A055165, Jan 15 2007
a(0)=1 prepended by Alois P. Heinz, May 29 2024
STATUS
approved

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Last modified July 21 03:36 EDT 2024. Contains 374463 sequences. (Running on oeis4.)