OFFSET
1,2
COMMENTS
The corresponding values of y of this Pell equation are in A174773.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..200
Index entries for linear recurrences with constant coefficients, signature (70,-1).
FORMULA
a(n) = 70*a(n-1)-a(n-2) with a(1)=1, a(2)=35.
G.f.: x*(1-35*x)/(1-70*x+x^2).
MATHEMATICA
Transpose[NestList[{#[[2]], 70#[[2]]-#[[1]]}&, {1, 35}, 20]][[1]] (* Harvey P. Dale, Mar 06 2011 *)
LinearRecurrence[{70, -1}, {1, 35}, 230] (* Vincenzo Librandi, Dec 20 2011 *)
PROG
(Magma) I:=[1, 35]; [n le 2 select I[n] else 70*Self(n-1)-Self(n-2): n in [1..20]];
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Apr 13 2010
STATUS
approved