A040874 -id:A040874 - cp's OEIS frontend

A042749 Denominators of continued fraction convergents to sqrt(905).

1, 12, 721, 8664, 520561, 6255396, 375844321, 4516387248, 271359079201, 3260825337660, 195920879338801, 2354311377403272, 141454603523535121, 1699809553659824724, 102130027823113018561, 1227260143431016047456, 73737738633684075865921

Offset: 0

N. J. A. Sloane

Vincenzo Librandi, Table of n, a(n) for n = 0..200
Index entries for linear recurrences with constant coefficients, signature (0, 722, 0, -1).

Cf. A042748, A040874.

Denominator[Convergents[Sqrt[905], 30]] (* Vincenzo Librandi, Jan 28 2014 *)
LinearRecurrence[{0,722,0,-1},{1,12,721,8664},20] (* Harvey P. Dale, Nov 08 2017 *)

G.f.: -(x^2-12*x-1) / (x^4-722*x^2+1). - Colin Barker, Dec 22 2013

Additional term from Colin Barker, Dec 22 2013

A212655 Denominator of Bernoulli(2*n,1/2) / Period of length 2: repeat 12, 60.

Original entry on oeis.org

1, 4, 112, 64, 2816, 93184, 4096, 278528, 8716288, 2883584

Offset: 1

Paul Curtz, Apr 14 2013

See A165949(n) = (A027642(n+1)=A027762(n))/A165734(n).

a(n) is divisible by 4^(n-1).

			a(1) = (B(2,1/2)=12)/12=1, a(2)=240/60=4, a(3)=1344/12=112, a(4)=3840/60=64.

Cf. A000302.

a(n) = A033469(n)/A040874(n).

a(n) = 4^(n-1) * A165949(n).

cp's OEIS Frontend

A042749 Denominators of continued fraction convergents to sqrt(905).

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