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A064486
Period of continued fraction for square roots of primorials.
0
1, 2, 2, 2, 2, 4, 2, 36, 38, 244, 244, 1830, 3422, 10626, 3828, 20970, 580384, 4197850, 18395762, 76749396, 166966158, 1492773346, 2307891442, 30021987038, 150709818548, 20897087728
OFFSET
1,2
FORMULA
a(n) = A003285(A002110(n)). - Michel Marcus, Sep 26 2019
EXAMPLE
n=6: cfrac(sqrt(30030),'periodic','quotients')=[[173], [3, 2, 3, 346]], so a(6)=4
MAPLE
with(numtheory): [seq(nops(cfrac(sqrt(product(ithprime(j), j=1..k)), 'periodic', 'quotients')[2]), k=1..14)];
MATHEMATICA
Table[Length[Part[ContinuedFraction[Sqrt[q[u]]], 2]], {u, 1, 18}]
CROSSREFS
Sequence in context: A153436 A354359 A367130 * A153437 A023153 A023159
KEYWORD
nonn,more
AUTHOR
Labos Elemer, Oct 04 2001
EXTENSIONS
a(19)-a(22) from Daniel Suteu, Jan 24 2019
a(23)-a(24) from Chai Wah Wu, Sep 25 2019
a(25)-a(26) from Chai Wah Wu, Sep 26 2019
STATUS
approved