|
| |
| |
|
|
|
6040, 14040, 22040, 30040, 38040, 46040, 54040, 62040, 70040, 78040, 86040, 94040, 102040, 110040, 118040, 126040, 134040, 142040, 150040, 158040, 166040, 174040, 182040, 190040, 198040, 206040, 214040, 222040, 230040, 238040, 246040, 254040
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
COMMENTS
| The identity (80000*n^2-39200*n+4801)^2-(100*n^2-49*n+6)*(8000*n-1960)^2=1 can be written as A157653(n)^2-A157651(n)*a(n)^2=1.
|
|
|
LINKS
| Vincenzo Librandi, Table of n, a(n) for n = 1..10000
Vincenzo Librandi, X^2-AY^2=1
Index to sequences with linear recurrences with constant coefficients, signature (2,-1).
|
|
|
FORMULA
| a(n) = 2*a(n-1) - a(n-2).
G.f.: x*(6040+1960*x)/(x-1)^2.
|
|
|
MATHEMATICA
| LinearRecurrence[{2, -1}, {6040, 14040}, 40]
|
|
|
PROG
| (MAGMA) I:=[6040, 14040]; [n le 2 select I[n] else 2*Self(n-1)-Self(n-2): n in [1..40]];
(PARI) a(n) = 8000*n - 1960.
|
|
|
CROSSREFS
| Cf. A157651, A157653.
Sequence in context: A203352 A064248 A202895 * A175160 A184195 A157267
Adjacent sequences: A157649 A157650 A157651 * A157653 A157654 A157655
|
|
|
KEYWORD
| nonn,easy
|
|
|
AUTHOR
| Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 03 2009
|
| |
|
|
