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A199565
(7*9^n+1)/4.
1
2, 16, 142, 1276, 11482, 103336, 930022, 8370196, 75331762, 677985856, 6101872702, 54916854316, 494251688842, 4448265199576, 40034386796182, 360309481165636, 3242785330490722, 29185067974416496, 262665611769748462
OFFSET
0,1
FORMULA
a(n) = 2*A187709(n).
a(n) = 9*a(n-1)-2.
a(n) = 10*a(n-1)-9*a(n-2).
G.f.: 2*(1-2*x)/((1-x)*(1-9*x)).
MATHEMATICA
LinearRecurrence[{10, -9}, {2, 16}, 30] (* Harvey P. Dale, Mar 14 2015 *)
PROG
(Magma) [(7*9^n+1)/4: n in [0..30]];
CROSSREFS
Sequence in context: A348618 A151402 A365526 * A003768 A214767 A300412
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Nov 08 2011
STATUS
approved