A014767 Order of shuffle group on n cards {0..n-1} generated by i->n-1-i and i->min{2i,2n-1-2i}.

1, 2, 6, 12, 60, 120, 5040, 32, 181440, 3628800, 39916800, 95040, 3113510400, 87178291200, 1307674368000, 80, 177843714048000, 6402373705728000, 121645100408832000, 1216451004088320000, 25545471085854720000

Offset

1,2

References

J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 323.

Links

Table of n, a(n) for n=1..21.

Prog

(Magma) S := function(n) G := Sym({0..n-1}); p := &*[ G | (i, n-1-i) : i in [ 0..Floor((n-2)/2) ] ];
q := G![ Min(2*i, 2*n-1-2*i):i in [ 0..n-1 ] ]; return Order(sub<G | p, q >); end function;

Crossrefs

Sequence in context: A138570 A161887 A139315 * A002319 A195307 A101657

Adjacent sequences: A014764 A014765 A014766 * A014768 A014769 A014770

Keyword

nonn,easy,nice

Author

N. J. A. Sloane

Status

approved