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A041097
Denominators of continued fraction convergents to sqrt(56).
2
1, 2, 29, 60, 869, 1798, 26041, 53880, 780361, 1614602, 23384789, 48384180, 700763309, 1449910798, 20999514481, 43448939760, 629284671121, 1302018282002, 18857540619149, 39017099520300, 565096933903349, 1169210967326998, 16934050476481321, 35037311920289640
OFFSET
0,2
FORMULA
G.f.: -(x^2-2*x-1) / (x^4-30*x^2+1). - Colin Barker, Nov 12 2013
a(n) = 30*a(n-2) - a(n-4). - Vincenzo Librandi, Dec 11 2013
MATHEMATICA
Denominator[Convergents[Sqrt[56], 30]] (* Vincenzo Librandi, Dec 11 2013 *)
LinearRecurrence[{0, 30, 0, -1}, {1, 2, 29, 60}, 30] (* Harvey P. Dale, Dec 09 2014 *)
PROG
(Magma) I:=[1, 2, 29, 60]; [n le 4 select I[n] else 30*Self(n-2)-Self(n-4): n in [1..30]]; // Vincenzo Librandi, Dec 11 2013
CROSSREFS
KEYWORD
nonn,cofr,easy,frac
AUTHOR
EXTENSIONS
More terms from Colin Barker, Nov 12 2013
STATUS
approved