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A166867
a(n) = Pell(n+3) - Jacobsthal(n+4).
1
0, 1, 8, 27, 84, 237, 644, 1695, 4376, 11129, 28000, 69859, 173180, 427141, 1049308, 2569447, 6275584, 15295377, 37215864, 90426155, 219466276, 532154909, 1289368500, 3122076719, 7555891560, 18278599081, 44202568208, 106862692467
OFFSET
0,3
FORMULA
G.f.: x(1+5x+2x^2)/((1-x-2x^2)(1-2x-x^2)).
a(n) = A166868(n) + A097076(n+1) - A000129(n+2).
a(n) = 3*a(n-1) + a(n-2) - 5*a(n-3) - 2*a(n-4). - G. C. Greubel, May 25 2016
MATHEMATICA
LinearRecurrence[{3, 1, -5, -2}, {0, 1, 8, 27}, 50] (* G. C. Greubel, May 25 2016 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Oct 22 2009
STATUS
approved