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

Offset: 0

Author

N. J. A. Sloane, Sep 06 2003

Keywords

• nonn

References

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

Crossrefs

Cf. A057649, A072345, A072346.

Formula

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