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A093458
Partial products of A073846.
1
1, 2, 8, 24, 144, 720, 5760, 40320, 362880, 3991680, 39916800, 518918400, 6227020800, 105859353600, 1482030950400, 28158588057600, 422378820864000, 9714712879872000, 155435406077952000, 4507626776260608000
OFFSET
0,2
COMMENTS
a(n-2) is the number of elements in the largest conjugacy class of A_n, the alternating group on n letters. Cf. A059171. [Geoffrey Critzer, Mar 26 2013]
FORMULA
a(n) = prime(1) * composite(1) * prime(2) * composite(2) * ... * prime(n/2) * composite(n/2) if n is even else a(n) = prime(1) * composite(1) * prime(2) * composite(2) * ... * prime((n+1)/2). a(0) = 1.
MATHEMATICA
g[list_]:=Total[list]! / Apply[Times, list] / Apply[Times, Table[Count[list, n]!, {n, 1, 20}]];
f[list_]:=Apply[Plus, Table[Count[list, n], {n, 2, 20, 2}]];
Drop[Table[Max[Map[g, Select[Partitions[n], EvenQ[f[#]]&]]], {n, 1, 20}]]
(* Geoffrey Critzer, Mar 26 2013 *)
CROSSREFS
Sequence in context: A087982 A176475 A145238 * A242456 A353779 A088994
KEYWORD
less,nonn
AUTHOR
Amarnath Murthy, Apr 03 2004
EXTENSIONS
More terms from David Wasserman, Sep 28 2006
STATUS
approved