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A041741 Denominators of continued fraction convergents to sqrt(390). 2
1, 1, 3, 4, 155, 159, 473, 632, 24489, 25121, 74731, 99852, 3869107, 3968959, 11807025, 15775984, 611294417, 627070401, 1865435219, 2492505620, 96580648779, 99073154399, 294726957577, 393800111976, 15259131212665, 15652931324641, 46564993861947 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..200

Index entries for linear recurrences with constant coefficients, signature (0,0,0,158,0,0,0,-1).

FORMULA

G.f.: -(x^2-x-1)*(x^4+4*x^2+1) / (x^8-158*x^4+1). - Colin Barker, Nov 23 2013

a(n) = 158*a(n-4) - a(n-8) for n>7. - Vincenzo Librandi, Dec 23 2013

MATHEMATICA

Denominator[Convergents[Sqrt[390], 30]] (* Vincenzo Librandi, Dec 23 2013 *)

LinearRecurrence[{0, 0, 0, 158, 0, 0, 0, -1}, {1, 1, 3, 4, 155, 159, 473, 632}, 30] (* Harvey P. Dale, Aug 06 2015 *)

PROG

(MAGMA) I:=[1, 1, 3, 4, 155, 159, 473, 632]; [n le 8 select I[n] else 158*Self(n-4)-Self(n-8): n in [1..40]]; // Vincenzo Librandi, Dec 23 2013

CROSSREFS

Cf. A041740, A040370.

Sequence in context: A290282 A077032 A041595 * A041903 A156513 A082213

Adjacent sequences:  A041738 A041739 A041740 * A041742 A041743 A041744

KEYWORD

nonn,frac,easy

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Colin Barker, Nov 23 2013

STATUS

approved

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Last modified March 22 10:07 EDT 2019. Contains 321421 sequences. (Running on oeis4.)