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A123279
a(n) = product of the first n integers from among those positive integers which are coprime to n.
0
1, 3, 8, 105, 144, 85085, 5760, 2027025, 3203200, 4216455243, 43545600, 29248404810625, 6706022400, 1305433904506875, 1707444076642304, 191898783962510625, 376610217984000, 232876694951587194633125
OFFSET
1,2
EXAMPLE
The first 4 positive integers which are coprime to 4 are 1,3,5,7. So a(4) = 1*3*5*7 = 105.
MATHEMATICA
f[n_] := Block[{c = n, k = 0, p = 1}, While[c > 0, k++; While[GCD[k, n] > 1, k++ ]; c--; p *= k; ]; p]; Table[f[n], {n, 20}] (* Ray Chandler, Dec 14 2006 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Leroy Quet, Dec 11 2006
EXTENSIONS
Extended by Ray Chandler, Dec 14 2006
STATUS
approved