A279285 Self-composition of the Pell numbers; g.f.: A(x) = G(G(x)), where G(x) = g.f. of A000129.
0, 1, 4, 18, 82, 377, 1740, 8045, 37226, 172314, 797744, 3693493, 17101128, 79180525, 366618808, 1697509962, 7859781454, 36392245541, 168502887396, 780199897985, 3612471696230, 16726421117538, 77446465948772, 358591660029577, 1660346632032144, 7687716275234809, 35595568065121900, 164814155562334914
Offset: 0
Links
- N. J. A. Sloane, Transforms
- Eric Weisstein's World of Mathematics, Pell Number
- Index entries for linear recurrences with constant coefficients, signature (6,-5,-6,-1).
Programs
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Mathematica
CoefficientList[Series[x (1 - 2 x - x^2)/(1 - 6 x + 5 x^2 + 6 x^3 + x^4), {x, 0, 27}], x] LinearRecurrence[{6, -5, -6, -1}, {0, 1, 4, 18}, 28]
Formula
G.f.: x*(1 - 2*x - x^2)/(1 - 6*x + 5*x^2 + 6*x^3 + x^4).
a(n) = 6*a(n-1) - 5*a(n-2) - 6*a(n-3) - a(n-4).