OFFSET
1,1
COMMENTS
The identity (128*n-1)^2 - (64*n^2-n)*(16)^2 = 1 can be written as a(n)^2 - A157948(n)*(16)^2 = 1. - Vincenzo Librandi, Jan 29 2012
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..10000
E. J. Barbeau, Polynomial Excursions, Chapter 10:Diophantine equations (2010), pages 84-85 (row 14 in the first table at p. 85, case d(t) = t*(8^2*t-1)).
Vincenzo Librandi, X^2-AY^2=1 [broken link]
Index entries for linear recurrences with constant coefficients, signature (2,-1).
FORMULA
a(n) = 2*a(n-1) - a(n-2). - Vincenzo Librandi, Jan 29 2012
G.f.: x*(127+x)/(1-x)^2. - Vincenzo Librandi, Jan 29 2012
PROG
(PARI) for(n=1, 40, print1(128*n - 1", ")); \\ Vincenzo Librandi, Jan 29 2012
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Mar 10 2009
STATUS
approved