A188659 Decimal expansion of (1+sqrt(26))/5.

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

Offset

1,2

Comments

Decimal expansion of the shape of a (2/5)-extension rectangle; see A188640 for definitions of shape and r-extension rectangle. Briefly, shape=length/width, and an r-extension rectangle is composed of two rectangles of shape 1/r when r<1.

The continued fraction of the constant is 1, 4, 1, 1, 4, 1, ... = A146325.

Links

Table of n, a(n) for n=1..130.

Formula

Equals exp(arcsinh(1/5)). - Amiram Eldar, Jul 04 2023

Example

1.219803902718556966005644821804556397912754189219919281516994...

Mathematica

RealDigits[(1 + Sqrt[26])/5, 10, 111][[1]] (* Robert G. Wilson v, Aug 18 2011 *)

Crossrefs

Cf. A146325, A188640, A188658, A188729, A188730, A010481.

Sequence in context: A021459 A133169 A133175 * A042977 A198106 A243261

Adjacent sequences: A188656 A188657 A188658 * A188660 A188661 A188662

Keyword

nonn,cons,easy

Author

Clark Kimberling, Apr 09 2011

Status

approved