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 A099368 Twice Chebyshev's polynomials of the first kind, T(n,x), evaluated at x=51/2. 4
 2, 51, 2599, 132498, 6754799, 344362251, 17555720002, 894997357851, 45627309530399, 2326097788692498, 118585359913786999, 6045527257814444451, 308203304788622880002, 15712323016961952435651, 801020270560270951338199 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS a(n) and b(n):= A097836(n-1) with b(0) = 0 are the improper and proper nonnegative solutions of the Pell equation a(n)^2 - 53*(7*b(n))^2 = +4. - Wolfdieter Lang, Jun 27 2013 LINKS Indranil Ghosh, Table of n, a(n) for n = 0..584 Tanya Khovanova, Recursive Sequences Index entries for linear recurrences with constant coefficients, signature (51, -1). FORMULA a(n)=51*a(n-1)-a(n-2), n >= 1; a(-1)=51, a(0)=2. a(n) = S(n, 51) - S(n-2, 51) = 2*T(n, 51/2) with S(n, x) := U(n, x/2), S(-1, x) := 0, S(-2, x) := -1. S(n, 51)=A097836(n). U-, resp. T-, are Chebyshev's polynomials of the second, resp. first, case. See A049310 and A053120. a(n)= ap^n + am^n, with ap:=(51 + 7*sqrt(53))/2 and am:=(51 - 7*sqrt(53))/2. G.f.: (2-51*x)/(1-51*x+x^2). MATHEMATICA LinearRecurrence[{51, -1}, {2, 51}, 15] (* or *) CoefficientList[Series[(2 - 51 x)/(1 - 51 x + x^2), {x, 0, 14}], x] (* Michael De Vlieger, Feb 08 2017 *) CROSSREFS Sequence in context: A222850 A089304 A210907 * A132492 A030264 A129742 Adjacent sequences:  A099365 A099366 A099367 * A099369 A099370 A099371 KEYWORD nonn,easy AUTHOR Wolfdieter Lang, Oct 18 2004 STATUS approved

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Last modified September 22 18:50 EDT 2018. Contains 315270 sequences. (Running on oeis4.)