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A108778 Continued fraction expansion of the Madelung constant for the NaCl structure (A085469). 2
1, 1, 2, 1, 24, 1, 10, 1, 1, 52, 1, 8, 1, 1, 1, 4, 2, 27, 2, 3, 1, 4, 1, 1, 1, 4, 2, 2, 1, 3, 1, 2, 1, 2, 1, 1, 3, 1, 51, 1, 4, 3, 3, 4, 1, 2, 1, 14, 1, 1, 1, 1, 1, 4, 7, 1, 3, 38, 4, 1, 2, 1, 2, 1, 1, 1, 6, 4, 5, 1, 14, 2, 18, 1, 10, 2, 5, 2, 2, 2, 9, 1, 4, 1, 23, 1, 2, 1, 2, 3, 132, 343, 2, 1, 1, 4, 3, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Increasing PQ's: 1, 2, 24, 52, 132, 343, 664, 1329, 2136, ....

LINKS

Harry J. Smith, Table of n, a(n) for n = 1..1794

EXAMPLE

1.7475645946331821906362... = 1 + 1/(1 + 1/(2 + 1/(1 + 1/(24 + ...)))). - Harry J. Smith, Apr 23 2009

MATHEMATICA

ContinuedFraction[ 12Pi*Sum[ Sech[ Pi/2*Sqrt[(2j + 1)^2 + (2k + 1)^2]]^2, {j, 0, 36}, {k, 0, 36}], 98]

CROSSREFS

Cf. A085469.

Sequence in context: A255861 A059360 A279308 * A271530 A062763 A243147

Adjacent sequences:  A108775 A108776 A108777 * A108779 A108780 A108781

KEYWORD

cofr,nonn

AUTHOR

Robert G. Wilson v, Jul 18 2005

EXTENSIONS

Definition corrected by Leslie Glasser, Jan 24 2011

Definition corrected by Andrey Zabolotskiy, Jul 30 2020

STATUS

approved

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Last modified April 14 21:21 EDT 2021. Contains 342962 sequences. (Running on oeis4.)