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A041409
Denominators of continued fraction convergents to sqrt(219).
2
1, 1, 4, 5, 144, 149, 591, 740, 21311, 22051, 87464, 109515, 3153884, 3263399, 12944081, 16207480, 466753521, 482961001, 1915636524, 2398597525, 69076367224, 71474964749, 283501261471, 354976226220, 10222835595631, 10577811821851, 41956271061184
OFFSET
0,3
FORMULA
G.f.: -(x^2-x-1)*(x^4+5*x^2+1) / (x^8-148*x^4+1). - Colin Barker, Nov 17 2013
a(n) = 148*a(n-4) - a(n-8) for n>7. - Vincenzo Librandi, Dec 17 2013
MATHEMATICA
Denominator[Convergents[Sqrt[219], 30]] (* Vincenzo Librandi, Dec 17 2013 *)
PROG
(Magma) I:=[1, 1, 4, 5, 144, 149, 591, 740]; [n le 8 select I[n] else 148*Self(n-4)-Self(n-8): n in [1..40]]; // Vincenzo Librandi, Dec 17 2013
CROSSREFS
Sequence in context: A113942 A073129 A270551 * A101076 A331578 A355705
KEYWORD
nonn,frac,easy
AUTHOR
EXTENSIONS
More terms from Colin Barker, Nov 17 2013
STATUS
approved