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A158132
144n^2 + 2n.
2
146, 580, 1302, 2312, 3610, 5196, 7070, 9232, 11682, 14420, 17446, 20760, 24362, 28252, 32430, 36896, 41650, 46692, 52022, 57640, 63546, 69740, 76222, 82992, 90050, 97396, 105030, 112952, 121162, 129660, 138446, 147520, 156882, 166532
OFFSET
1,1
COMMENTS
The identity (144*n+1)^2-(144*n^2+2*n)*(12)^2=1 can be written as A158133(n)^2-a(n)*(12)^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*(12^2*t+2))
FORMULA
a(n) = 3*a(n-1) -3*a(n-2) +a(n-3).
G.f.: x*(-142*x-146)/(x-1)^3.
MATHEMATICA
LinearRecurrence[{3, -3, 1}, {146, 580, 1302}, 50]
PROG
(Magma) I:=[146, 580, 1302]; [n le 3 select I[n] else 3*Self(n-1)-3*Self(n-2)+1*Self(n-3): n in [1..50]];
(PARI) a(n) = 144*n^2 + 2*n
CROSSREFS
Cf. A158133.
Sequence in context: A238028 A179572 A211838 * A043431 A183662 A183654
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Mar 13 2009
STATUS
approved