A072168 - OEIS

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A072168

Floor of ratio of volume of n-dimensional cube of side 2 to volume of n-dimensional ball of radius 1.

1, 1, 1, 1, 3, 6, 12, 27, 63, 155, 401, 1086, 3067, 8995, 27340, 85905, 278484, 929713, 3191200, 11245602, 40631627, 150342632, 569071745, 2201355133, 8694775794, 35035655103, 143916920871, 602218550964, 2565370007348, 11118142868084, 48994958103507

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,5

REFERENCES

J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 9.

LINKS

Table of n, a(n) for n=0..30.

FORMULA

a(n) = floor(2^n * Gamma(n/2+1) / Pi^(n/2)).

CROSSREFS

Cf. A057649, A072345, A072346.

Sequence in context: A088688 A290997 A052103 * A292290 A018011 A025208

Adjacent sequences: A072165 A072166 A072167 * A072169 A072170 A072171

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Sep 06 2003

STATUS

approved