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A130834 Decimal expansion of the limit of the (2/n^2)-th power of the number of distinct dimer coverings on the n X n square grid, n even, as n goes to infinity. 9
1, 7, 9, 1, 6, 2, 2, 8, 1, 2, 0, 6, 9, 5, 9, 3, 4, 2, 4, 7, 3, 0, 5, 4, 7, 0, 8, 9, 3, 4, 2, 9, 8, 2, 4, 3, 2, 2, 6, 8, 1, 3, 4, 3, 9, 3, 1, 3, 2, 9, 5, 4, 7, 6, 7, 7, 6, 7, 5, 8, 3, 4, 7, 6, 4, 9, 9, 4, 2, 5, 0, 7, 4, 2, 3, 7, 6, 5, 7, 8, 9, 6, 0, 1, 3, 2, 2, 6 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET
1,2
REFERENCES
S. R. Finch, Mathematical Constants, Cambridge, 2003, p. 232.
LINKS
S. R. Finch, Several Constants Arising in Statistical Mechanics, Ann. Comb. 3(2-4) (1999), 323-335.
FORMULA
Equals exp(2*A006752/A000796).
Equals A097469^2. - Vaclav Kotesovec, Dec 30 2020
EXAMPLE
1.791622812069593424730547089...
MAPLE
evalf(exp(2*Catalan/Pi));
MATHEMATICA
RealDigits[Exp[(2*Catalan)/Pi], 10, 120][[1]] (* Harvey P. Dale, Jul 17 2011 *)
PROG
(PARI) exp(2*Catalan/Pi) \\ Charles R Greathouse IV, Jul 15 2014
(Magma) R:=RealField(100); Exp(2*Catalan(R)/Pi(R)); // G. C. Greubel, Aug 23 2018
CROSSREFS
Cf. A000796 (Pi), A006752 (Catalan), A229728.
Sequence in context: A222135 A086318 A244674 * A132806 A016629 A154203
KEYWORD
cons,nonn
AUTHOR
R. J. Mathar, Jul 18 2007
STATUS
approved

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Last modified May 20 06:19 EDT 2024. Contains 372703 sequences. (Running on oeis4.)