login
A042740
Numerators of continued fraction convergents to sqrt(901).
3
30, 1801, 108090, 6487201, 389340150, 23366896201, 1402403112210, 84167553628801, 5051455620840270, 303171504804045001, 18195341743863540330, 1092023676136616464801, 65539615909940851428390, 3933468978272587702168201, 236073678312265202981520450, 14168354167714184766593395201
OFFSET
0,1
FORMULA
From Philippe Deléham, Nov 23 2008: (Start)
a(n) = 60*a(n-1)+a(n-2) for n>1, a(0)=30, a(1)=1801.
G.f.: (30+x)/(1-60*x-x^2). (End)
E.g.f.: exp(30*x)*(30*cosh(sqrt(901)*x) + sqrt(901)*sinh(sqrt(901)*x)). - Stefano Spezia, May 14 2023
MATHEMATICA
Numerator[Convergents[Sqrt[901], 30]] (* Vincenzo Librandi, Dec 03 2013 *)
CROSSREFS
Cf. A042741.
Sequence in context: A202384 A202369 A042743 * A367392 A282126 A112003
KEYWORD
nonn,frac,easy
STATUS
approved