A143233 Decimal expansion of the dimer constant.

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

Offset

0,1

Links

G. C. Greubel, Table of n, a(n) for n = 0..10000

Yong Kong, Monomer-dimer model in two-dimensional rectangular lattices with fixed dimer density, arXiv:cond-mat/0610690

Eric Weisstein's World of Mathematics, Domino Tiling

Formula

Equals Catalan/Pi.

Also equals integral_{t=-Pi..Pi} arccosh(sqrt(cos(t)+3)/sqrt(2))/(4*Pi) dt. - Jean-François Alcover, May 14 2014

Example

0.29156090403081878013...

Mathematica

RealDigits[Catalan/Pi, 10, 100][[1]] (* G. C. Greubel, Aug 24 2018 *)

Prog

(PARI) default(realprecision, 100); Catalan/Pi \\ G. C. Greubel, Aug 24 2018
(Magma) SetDefaultRealField(RealField(100)); R:=RealField(); Catalan(R)/Pi(R); // G. C. Greubel, Aug 24 2018

Crossrefs

Cf. A000796, A006752.

Sequence in context: A244807 A021347 A011278 * A266264 A011216 A096250

Adjacent sequences: A143230 A143231 A143232 * A143234 A143235 A143236

Keyword

nonn,cons

Author

Eric W. Weisstein, Jul 31 2008

Status

approved