OFFSET
1,2
COMMENTS
The corresponding values of y of this Pell equation are in A174776.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..200
Index entries for linear recurrences with constant coefficients, signature (50,-1).
FORMULA
a(n) = 50*a(n-1)-a(n-2) with a(1)=1, a(2)=25.
G.f.: x*(1-25*x)/(1-50*x+x^2).
MATHEMATICA
LinearRecurrence[{50, -1}, {1, 25}, 30]
Rest[CoefficientList[Series[x (1-25x)/(1-50x+x^2), {x, 0, 20}], x]] (* Harvey P. Dale, Aug 10 2021 *)
PROG
(Magma) I:=[1, 25]; [n le 2 select I[n] else 50*Self(n-1)-Self(n-2): n in [1..20]];
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Apr 13 2010
STATUS
approved