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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. 8
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

Nathaniel Johnston, Table of n, a(n) for n = 1..10000

S. R. Finch, Several Constants Arising in Statistical Mechanics, Annals Combinat. vol 3 (1999) issue (2-4) pp. 323-335.

FORMULA

Equals exp(2*A006752/A000796).

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

CROSSREFS

Cf. A229728.

Sequence in context: A222135 A086318 A244674 * A132806 A016629 A154203

Adjacent sequences:  A130831 A130832 A130833 * A130835 A130836 A130837

KEYWORD

cons,nonn

AUTHOR

R. J. Mathar, Jul 18 2007

STATUS

approved

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Last modified July 26 22:38 EDT 2017. Contains 289840 sequences.