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URL: https://oeis.org/A165230

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A165230
a(0)=1, a(1)=7, a(n)=14*a(n-1)-7*a(n-2) for n>1 .
2
1, 7, 91, 1225, 16513, 222607, 3000907, 40454449, 545355937, 7351801975, 99107736091, 1336045691449, 18010885527649, 242800077546943, 3273124886963659, 44124147874662625, 594826196036531137, 8018697709388797543, 108097984559187447643, 1457240899862902684201
OFFSET
0,2
FORMULA
G.f.: (1-7*x)/(1-14*x+7*x^2) .
a(n) = (1/2)*((7+sqrt(42))^n+(7-sqrt(42))^n). [Paolo P. Lava, Sep 16 2009]
MATHEMATICA
LinearRecurrence[{14, -7}, {1, 7}, 20] (* Harvey P. Dale, Dec 18 2016 *)
CROSSREFS
Sequence in context: A249640 A389564 A248226 * A346939 A156712 A004368
KEYWORD
nonn,easy
AUTHOR
Philippe Deléham, Sep 09 2009
EXTENSIONS
More terms from Harvey P. Dale, Dec 18 2016
STATUS
approved