login
A157758
a(n) = 297754*n - 244754.
3
53000, 350754, 648508, 946262, 1244016, 1541770, 1839524, 2137278, 2435032, 2732786, 3030540, 3328294, 3626048, 3923802, 4221556, 4519310, 4817064, 5114818, 5412572, 5710326, 6008080, 6305834, 6603588, 6901342, 7199096
OFFSET
1,1
COMMENTS
The identity (15780962*n^2-25943924*n+10662963)^2-(2809*n^2-4618*n+1898)*(297754*n-244754)^2=1 can be written as A157759(n)^2-A157757(n)*a(n)^2=1.
FORMULA
a(n) = 2*a(n-1) - a(n-2).
G.f.: x*(53000 + 244754*x)/(1-x)^2.
MATHEMATICA
LinearRecurrence[{2, -1}, {53000, 350754}, 30]
PROG
(Magma) I:=[53000, 350754]; [n le 2 select I[n] else 2*Self(n-1)-Self(n-2): n in [1..40]];
(PARI) a(n) = 297754*n - 244754;
CROSSREFS
Sequence in context: A309556 A206092 A233965 * A250696 A250681 A031833
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Mar 06 2009
STATUS
approved