login
A042456
Numerators of continued fraction convergents to sqrt(756).
2
27, 55, 2997, 6049, 329643, 665335, 36257733, 73180801, 3988020987, 8049222775, 438646050837, 885341324449, 48247077571083, 97379496466615, 5306739886768293, 10710859270003201, 583693140466941147
OFFSET
0,1
FORMULA
G.f.: (27 +55*x +27*x^2 -x^3)/(1 -110*x^2 +x^4). - Vincenzo Librandi, Nov 25 2013
a(n) = 110*a(n-2) - a(n-4). - Vincenzo Librandi, Nov 25 2013
MATHEMATICA
Numerator[Convergents[Sqrt[756], 30]] (* Harvey P. Dale, Sep 14 2012 *)
CoefficientList[Series[(27 + 55 x + 27 x^2 - x^3)/(1 - 110 x^2 + x^4), {x, 0, 30}], x] (* Vincenzo Librandi, Nov 25 2013 *)
PROG
(Magma) I:=[27, 55, 2997, 6049]; [n le 4 select I[n] else 110*Self(n-2)-Self(n-4): n in [1..30]]; // Vincenzo Librandi, Nov 25 2013
CROSSREFS
Cf. A042457.
Sequence in context: A042450 A042452 A042454 * A132768 A352266 A053180
KEYWORD
nonn,cofr,frac,easy
AUTHOR
STATUS
approved