A249863 Chebyshev S polynomial (A049310) evaluated at x = 26/7 and multiplied by powers of 7 (A000420).

1, 26, 627, 15028, 360005, 8623758, 206577463, 4948449896, 118537401609, 2839498396930, 68018625641339, 1629348845225244, 39030157319430733, 934945996889162102, 22396118210466108735, 536486719624549884112

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

Table of n, a(n) for n=0..15.

Index entries for linear recurrences with constant coefficients, signature (26,-49)

Index entries for sequences related to Chebyshev polynomials

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