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.

A177706 Period 5: repeat [1, 1, 1, 1, 2].

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2
Offset: 0

Views

Author

Klaus Brockhaus, May 11 2010

Keywords

Comments

Continued fraction expansion of (5+sqrt(65))/8.
Decimal expansion of 3704/33333.

Crossrefs

Cf. A130782 (repeat 1, 1, 2, 1, 1), A177707 (decimal expansion of (5+sqrt(65))/8).

Programs

  • Magma
    &cat[ [1, 1, 1, 1, 2]: k in [1..21] ];
  • Maple
    A177706:=n->floor(6*(n+1)/5)-floor(6*n/5): seq(A177706(n), n=0..100); # Wesley Ivan Hurt, Jul 24 2014
  • Mathematica
    Table[Floor[6 (n + 1)/5] - Floor[6 n/5], {n, 0, 100}] (* Wesley Ivan Hurt, Jul 24 2014 *)

Formula

a(n) = a(n-5) for n > 4; a(0) = 1, a(1) = 1, a(2) = 1, a(3) = 1, a(4) = 2.
G.f.: (1+x+x^2+x^3+2*x^4)/(1-x^5).
a(n) = A130782(n+3).
a(n+4) = A198517(n+2) + A198517(n+1) + A198517(n). - Bruno Berselli, Nov 02 2011
a(n) = floor((n+1)*6/5) - floor((n)*6/5). - Hailey R. Olafson, Jul 23 2014
a(n) = (2/5)*(3 + cos(4*(n-4)*Pi/5) + cos(2*(n+1)*Pi/5)). - Wesley Ivan Hurt, Oct 05 2018
a(n) = 2 - ((n+1)^4 mod 5). - Aaron J Grech, Aug 30 2024

A188656 Decimal expansion of (1+sqrt(65))/8.

Original entry on oeis.org

1, 1, 3, 2, 7, 8, 2, 2, 1, 8, 5, 3, 7, 3, 1, 8, 7, 0, 6, 5, 4, 5, 8, 2, 6, 6, 5, 3, 7, 8, 7, 9, 7, 1, 3, 9, 1, 3, 9, 1, 7, 9, 9, 5, 3, 8, 2, 0, 1, 0, 7, 1, 6, 7, 3, 4, 9, 2, 0, 7, 4, 0, 4, 8, 6, 5, 7, 9, 8, 4, 3, 6, 8, 8, 7, 8, 2, 1, 1, 0, 2, 5, 3, 7, 0, 0, 1, 9, 2, 8, 3, 3, 3, 9, 6, 5, 3, 8, 3, 0, 4, 5, 4, 6, 8, 0, 3, 0, 8, 2, 6, 7, 4, 9, 3, 2, 3, 9, 0, 2, 6, 7, 1, 8, 5, 8, 1, 5, 1, 5
Offset: 1

Views

Author

Clark Kimberling, Apr 09 2011

Keywords

Comments

Apart from the second digit the same as A177707.
Decimal expansion of the shape of a (1/4)-extension rectangle.
See A188640 for definitions of shape and r-extension rectangle.
A (1/4)-extension rectangle matches the continued fraction [1,7,1,1,7,1,1,7,1,1,7,1,1,7,...] for the shape L/W= (1+sqrt(65))/8. This is analogous to the matching of a golden rectangle to the continued fraction [1,1,1,1,1,1,1,...]. Specifically, for the (4/3)-extension rectangle, 1 square is removed first, then 7 squares, then 1 square, then 1 square, then 7 squares,..., so that the original rectangle is partitioned into an infinite collection of squares.

Examples

			length/width = 1.13278221853731870654582665....
		

Crossrefs

Programs

  • Mathematica
    RealDigits[(1 + Sqrt[65])/8, 10, 111][[1]] (* Robert G. Wilson v, Aug 19 2011 *)
Showing 1-2 of 2 results.