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 1-3 of 3 results.

A072560 Denominators of w(n) where w(1)=w(2)=w(3)=1, w(n)=(w(n-1)*w(n-2)+(w(n-1)+w(n-2))/3) / w(n-3).

Original entry on oeis.org

3, 9, 3, 3, 1, 3, 3, 9, 3, 3, 1, 3, 3, 9, 3, 1, 1, 1, 3, 9, 3, 3, 1, 3, 3, 9, 3, 3, 1, 3, 3, 9, 3, 1, 1, 1, 3, 9, 3, 3, 1, 3, 3, 9, 3, 3, 1, 3, 3, 9, 3, 1, 1, 1, 3, 9, 3, 3, 1, 3, 3, 9, 3, 3, 1, 3, 3, 9, 3, 1, 1, 1, 3, 9, 3, 3, 1, 3, 3, 9, 3, 3, 1, 3, 3, 9, 3, 1, 1, 1, 3, 9, 3, 3, 1, 3, 3, 9, 3, 3, 1, 3, 3, 9, 3
Offset: 1

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Author

Benoit Cloitre, Aug 06 2002

Keywords

Comments

Sequence contains 1,3 or 9 only and is periodic with period (3,9,3,3,1,3,3,9,3,3,1,3,3,9,3,1,1,1) of length 18.

Examples

			The sequence w() begins: 1, 1, 1, 5/3, 23/9, 17/3, 31/3, 25, 143/3, 353/3, 2039/9, 1685/3, 3251/3, 2689, 15571/3, ...
		

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1},{3, 9, 3, 3, 1, 3, 3, 9, 3, 3, 1, 3, 3, 9, 3, 1, 1, 1},105] (* Ray Chandler, Aug 25 2015 *)
    PadRight[{},120,{3,9,3,3,1,3,3,9,3,3,1,3,3,9,3,1,1,1}] (* Harvey P. Dale, Apr 04 2022 *)

A072561 Denominators of w(n) equals 3 where w(1)=w(2)=w(3)=1, w(n)=(w(n-1)*w(n-2)+(w(n-1)+w(n-2))/3) / w(n-3).

Original entry on oeis.org

1, 3, 4, 6, 7, 9, 10, 12, 13, 15, 19, 21, 22, 24, 25, 27, 28, 30, 31, 33, 37, 39, 40, 42, 43, 45, 46, 48, 49, 51, 55, 57, 58, 60, 61, 63, 64, 66, 67, 69, 73, 75, 76, 78, 79, 81, 82, 84, 85, 87, 91, 93, 94, 96, 97, 99, 100, 102, 103, 105, 109, 111, 112, 114, 115, 117, 118
Offset: 1

Views

Author

Benoit Cloitre, Aug 06 2002

Keywords

Comments

Denominators of w(k) are 1, 3 or 9.

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{1, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1},{1, 3, 4, 6, 7, 9, 10, 12, 13, 15, 19},67] (* Ray Chandler, Aug 25 2015 *)

Formula

lim n -> infinity a(n)/n = 9/5. sequence contains numbers of form (1+18k), (3+18k), (4+18k), (6+18k), (7+18k), (9+18k), (10+18k), (12+18k), (13+18k), (15+18k) k>=0.

Extensions

Corrected by Franklin T. Adams-Watters, Oct 25 2006

A072563 9*w(n) where : w(1)=w(2)=w(3)=1 w(n)=(w(n-1)*w(n-2)+(w(n-1)+w(n-2))/3) / w(n-3).

Original entry on oeis.org

9, 9, 9, 15, 23, 51, 93, 225, 429, 1059, 2039, 5055, 9753, 24201, 46713, 115935, 223799, 555459, 1072269, 2661345, 5137533, 12751251, 24615383, 61094895, 117939369, 292723209, 565081449, 1402521135, 2707467863, 6719882451
Offset: 1

Views

Author

Benoit Cloitre, Aug 06 2002

Keywords

Comments

All terms are integers.

Crossrefs

Formula

lim n -> infinity a(n+1)/a(n) = (1/6) * ( 7 + sqrt(21) ) = 1.93042928249263...
G.f.: x(15x^5+23x^4-39x^3-45x^2+9x+9)/(-x^6+6x^4-6x^2+1).
Showing 1-3 of 3 results.