

A153068


Denominators of the convergents of the continued fraction for L(2, chi3), where L(s, chi3) is the Dirichlet Lfunction for the nonprincipal character modulo 3.


3



1, 0, 1, 1, 4, 5, 9, 23, 32, 567, 599, 6557, 7156, 13713, 75721, 89434, 165155, 419744, 584899, 1004643, 1589542, 2594185, 6777912, 16150009, 22927921, 39077930, 62005851, 101083781, 264173413, 1157777433, 1421950846, 2579728279
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OFFSET

2,5


LINKS

Table of n, a(n) for n=2..29.


FORMULA

chi3(k) = Kronecker(3, k); chi3(k) is 0, 1, 1 when k reduced modulo 3 is 0, 1, 2, respectively; chi3 is A102283.
Series: L(2, chi3) = Sum_{k=1..infinity} chi3(k) k^{2} = 1  1/2^2 + 1/4^2  1/5^2 + 1/7^2  1/8^2 + 1/10^2  1/11^2 + ...


EXAMPLE

L(2, chi3) = 0.781302412896486296867187429624092... = [0; 1, 3, 1, 1, 2, 1, 17, 1, 10, 1, 1, 5, 1, 1, 2, 1, ...], the convergents of which are 0/1, 1/0, [0/1], 1/1, 3/4, 4/5, 7/9, 18/23, 25/32, 443/567, 468/599, 5123/6557, 5591/7156, ..., with brackets marking index 0. Those prior to index 0 are for initializing the recurrence.


MATHEMATICA

nmax = 100; cfrac = ContinuedFraction[(Zeta[2, 1/3]  Zeta[2, 2/3])/9, nmax + 1]; Join[ {1, 0}, Denominator[ Table[ FromContinuedFraction[ Take[cfrac, j] ], {j, 1, nmax + 1} ] ] ]


CROSSREFS

Cf. A086724, A153066, A153067.
Sequence in context: A240926 A041032 A041993 * A075116 A041079 A042715
Adjacent sequences: A153065 A153066 A153067 * A153069 A153070 A153071


KEYWORD

nonn,frac,easy


AUTHOR

Stuart Clary, Dec 17 2008


STATUS

approved



