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A092164
Let M = 2 X 2 matrix [ 1 2 / 5 4 ]; a(n) = (1,1) entry of M^n.
4
1, 11, 61, 371, 2221, 13331, 79981, 479891, 2879341, 17276051, 103656301, 621937811, 3731626861, 22389761171, 134338567021, 806031402131, 4836188412781, 29017130476691, 174102782860141, 1044616697160851
OFFSET
1,2
FORMULA
a(n) = (2*6^n + 5*(-1)^n)/7.
A092165 +(-1)^n.
a(n)=5*a(n-1)+6*a(n-2). G.f.: x*(1+6*x)/((1+x)*(1-6*x)). - R. J. Mathar, Apr 20 2009
MATHEMATICA
Table[ MatrixPower[{{1, 2}, {5, 4}}, n][[1, 1]], {n, 20}] (* Robert G. Wilson v, Apr 22 2004 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Jun Mizuki (suzuki32(AT)sanken.osaka-u.ac.jp), Apr 01 2004
EXTENSIONS
Edited by Robert G. Wilson v, Apr 22 2004
STATUS
approved