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A100996
a(1) = 1; a(n) is smallest positive integer such that a(n)*a(n-1)+1 is coprime to n.
0
1, 2, 2, 1, 1, 4, 1, 2, 2, 1, 1, 4, 1, 2, 3, 2, 1, 4, 1, 2, 2, 1, 1, 4, 2, 1, 1, 2, 1, 6, 1, 2, 2, 1, 1, 4, 1, 2, 2, 1, 1, 4, 1, 2, 3, 2, 1, 4, 1, 2, 2, 1, 1, 4, 2, 1, 1, 2, 1, 6, 1, 2, 2, 1, 1, 4, 1, 2, 2, 1, 1, 4, 1, 2, 3, 2, 1, 4, 1, 2, 2, 1, 1, 4, 2, 1, 1, 2, 1, 6, 3, 2, 2, 1, 1, 4, 1, 2, 2, 1, 1, 4, 1, 2, 5
OFFSET
1,2
MATHEMATICA
a[1] = 1; a[n_] := a[n] = Block[{k = 1}, While[ GCD[k*a[n - 1] + 1, n] != 1, k++ ]; k]; Table[ a[n], {n, 105}]
CROSSREFS
Sequence in context: A319700 A279104 A165509 * A232504 A292201 A343070
KEYWORD
nonn
AUTHOR
Leroy Quet, Jan 13 2005
EXTENSIONS
More terms from Robert G. Wilson v, Feb 11 2005
STATUS
approved