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 A051680 Number of n X n invertible matrices A over GF(3) such that A-I is invertible. 1
 1, 27, 6291, 13589289, 266377183929, 47123189360124723, 75095231825148137471259, 1077370264330489309698453375441, 139124702920688202983704723564457669361 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS FORMULA a(n) = 3^binomial(n,2)*b(n), with b(0)=1, b(n)=(3^n-1)*b(n-1)+(-1)^(n). - Vladeta Jovovic, Aug 20 2006 MATHEMATICA a[n_] := a[n] = 3^(n-1)*((3^n-1)*a[n-1] + (-1)^n*3^((n-3)*n/2+1)); a[1] = 1; Table[a[n], {n, 1, 9}] (* Jean-François Alcover, Jan 12 2012, after formula *) CROSSREFS Cf. A002820. Sequence in context: A059795 A211928 A123395 * A013828 A209261 A001321 Adjacent sequences:  A051677 A051678 A051679 * A051681 A051682 A051683 KEYWORD nonn,nice AUTHOR Vladeta Jovovic, Mar 17 2000 STATUS approved

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Last modified April 5 10:20 EDT 2020. Contains 333239 sequences. (Running on oeis4.)