login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A158330
484n - 1.
2
483, 967, 1451, 1935, 2419, 2903, 3387, 3871, 4355, 4839, 5323, 5807, 6291, 6775, 7259, 7743, 8227, 8711, 9195, 9679, 10163, 10647, 11131, 11615, 12099, 12583, 13067, 13551, 14035, 14519, 15003, 15487, 15971, 16455, 16939, 17423, 17907
OFFSET
1,1
COMMENTS
The identity (484*n-1)^2-(484*n^2-2*n)*(22)^2=1 can be written as a(n)^2-A158329(n)*(22)^2=1.
LINKS
Vincenzo Librandi, X^2-AY^2=1
E. J. Barbeau, Polynomial Excursions, Chapter 10: Diophantine equations (2010), pages 84-85 (row 15 in the first table at p. 85, case d(t) = t*(22^2*t-2)).
FORMULA
a(n) = 2*a(n-1)-a(n-2).
G.f.: x*(483+x)/(1-x)^2.
MATHEMATICA
LinearRecurrence[{2, -1}, {483, 967}, 50]
PROG
(Magma) I:=[483, 967]; [n le 2 select I[n] else 2*Self(n-1)-Self(n-2): n in [1..50]];
(PARI) a(n) = 484*n - 1.
CROSSREFS
Cf. A158329.
Sequence in context: A121734 A260976 A281047 * A288082 A251625 A156646
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Mar 16 2009
STATUS
approved