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A041966
Numerators of continued fraction convergents to sqrt(506).
2
22, 45, 2002, 4049, 180158, 364365, 16212218, 32788801, 1458919462, 2950627725, 131286539362, 265523706449, 11814329623118, 23894182952685, 1063158379541258, 2150210942035201, 95672439829090102, 193495090600215405
OFFSET
0,1
FORMULA
G.f.: (22 + 45*x + 22*x^2 - x^3)/(1 - 90*x^2 + x^4). - Vincenzo Librandi, Nov 12 2013
a(n) = 90*a(n-2) - a(n-4). - Vincenzo Librandi, Nov 12 2013
MATHEMATICA
Numerator[Convergents[Sqrt[506], 30]] (* or *) CoefficientList[Series[(22 + 45 x + 22 x^2 - x^3)/(1 - 90 x^2 + x^4), {x, 0, 30}], x] (* Vincenzo Librandi, Nov 12 2013 *)
PROG
(Magma) I:=[22, 45, 2002, 4049]; [n le 4 select I[n] else 90*Self(n-2)-Self(n-4): n in [1..25]]; // Vincenzo Librandi, Nov 12 2013
CROSSREFS
Cf. A041967.
Sequence in context: A041958 A041962 A041964 * A350321 A106838 A190614
KEYWORD
nonn,cofr,frac,easy,less
AUTHOR
STATUS
approved