cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-2 of 2 results.

A302330 a(0)=1, a(1)=97; for n>1, a(n) = 98*a(n-1) - a(n-2).

Original entry on oeis.org

1, 97, 9505, 931393, 91267009, 8943235489, 876345810913, 85872946233985, 8414672385119617, 824552020795488481, 80797683365572751521, 7917348417805334160577, 775819347261557174985025, 76022378683214797814371873, 7449417291607788628633458529
Offset: 0

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Author

Bruno Berselli, Apr 05 2018

Keywords

Crossrefs

Fifth row of the array A188646.
First bisection of A041275, A042151.
Similar sequences of the type cosh((2*n+1)*arccosh(k))/k are listed in A302329.

Programs

  • Mathematica
    LinearRecurrence[{98, -1}, {1, 97}, 20]
  • PARI
    x='x+O('x^99); Vec((1-x)/(1-98*x+x^2)) \\ Altug Alkan, Apr 06 2018

Formula

G.f.: (1 - x)/(1 - 98*x + x^2).
a(n) = a(-1-n).
a(n) = cosh((2*n + 1)*arccosh(5))/5.
a(n) = ((5 + 2*sqrt(6))^(2*n + 1) + 1/(5 + 2*sqrt(6))^(2*n + 1))/10.
a(n) = (1/5)*T(2*n+1, 5), where T(n,x) denotes the n-th Chebyshev polynomial of the first kind. - Peter Bala, Jul 08 2022

A041274 Numerators of continued fraction convergents to sqrt(150).

Original entry on oeis.org

12, 49, 1188, 4801, 116412, 470449, 11407188, 46099201, 1117788012, 4517251249, 109531817988, 442644523201, 10733000374812, 43374646022449, 1051724504913588, 4250272665676801, 103058268481156812, 416483346590304049
Offset: 0

Views

Author

Keywords

Crossrefs

Cf. A041275.

Programs

  • Mathematica
    Numerator[Convergents[Sqrt[150], 30]] (* Vincenzo Librandi, Nov 01 2013 *)
    LinearRecurrence[{0,98,0,-1}, {12, 49, 1188, 4801}, 20] (* Bruno Berselli, Nov 01 2013 *)

Formula

a(n) = 9602*a(n-4) - a(n-8) = 98*a(n-2) - a(n-4). - Vincenzo Librandi and Bruno Berselli, Nov 01 2013
G.f.: (3 + x)*(4 + 15*x - x^2)/((1 - 10*x + x^2)*(1 + 10*x + x^2)). [Bruno Berselli, Nov 01 2013]
Showing 1-2 of 2 results.