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 A249863 Chebyshev S polynomial (A049310) evaluated at x = 26/7 and multiplied by powers of 7 (A000420). 3
 1, 26, 627, 15028, 360005, 8623758, 206577463, 4948449896, 118537401609, 2839498396930, 68018625641339, 1629348845225244, 39030157319430733, 934945996889162102, 22396118210466108735, 536486719624549884112 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS This sequence appears in the solution of the curvature sequence of the touching circle and chord example given by Kival Ngaokrajang in A249458. See also the pair A249864(n) and a(n-1), with a(-1) = 0, for which details are given in A249864. LINKS Index entries for linear recurrences with constant coefficients, signature (26,-49) FORMULA a(n) = 7^n*S(n, 26/7) with Chebyshev's S polynomial (for S see the coefficient triangle A049310). O.g.f.: 1/(1 - 26*x + (7*x)^2). a(n) = 26*a(n-1) - 49*a(n-2), a(-1) = 0, a(0) = 1 . MATHEMATICA LinearRecurrence[{26, -49}, {1, 26}, 20] (* Harvey P. Dale, Jun 30 2017 *) PROG (MAGMA) I:=[1, 26]; [n le 2 select I[n] else 26*Self(n-1)-49*Self(n-2): n in [1..40]]; // Vincenzo Librandi, Nov 09 2014 CROSSREFS Cf. A000420, A049310, A249864, A248163. Sequence in context: A262076 A057010 A217636 * A014913 A285397 A106793 Adjacent sequences:  A249860 A249861 A249862 * A249864 A249865 A249866 KEYWORD nonn,easy AUTHOR Wolfdieter Lang, Nov 09 2014 STATUS approved

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Last modified August 20 18:56 EDT 2019. Contains 326154 sequences. (Running on oeis4.)