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 A157363 686n - 14. 3
 672, 1358, 2044, 2730, 3416, 4102, 4788, 5474, 6160, 6846, 7532, 8218, 8904, 9590, 10276, 10962, 11648, 12334, 13020, 13706, 14392, 15078, 15764, 16450, 17136, 17822, 18508, 19194, 19880, 20566, 21252, 21938, 22624, 23310, 23996, 24682 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The identity (4802*n^2-196*n+1)^2-(49*n^2-2*n)*(686*n-14)^2=1 can be written as A157364(n)^2-A157362(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 entries for linear recurrences with constant coefficients, signature (2,-1). FORMULA a(n) = 2*a(n-1) -a(n-2). G.f.: 14*x*(48+x)/(1-x)^2. E.g.f.: 14*(1 - (1-49*x)*exp(x)). - G. C. Greubel, Feb 02 2018 MATHEMATICA LinearRecurrence[{2, -1}, {672, 1358}, 50] PROG (MAGMA) I:=[672, 1358]; [n le 2 select I[n] else 2*Self(n-1)-Self(n-2): n in [1..40]]; (PARI) a(n) = 686*n-14. CROSSREFS Cf. A157362, A157364. Sequence in context: A053085 A057695 A233315 * A234732 A057805 A057796 Adjacent sequences:  A157360 A157361 A157362 * A157364 A157365 A157366 KEYWORD nonn,easy AUTHOR Vincenzo Librandi, Feb 28 2009 STATUS approved

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Last modified March 19 11:10 EDT 2019. Contains 321329 sequences. (Running on oeis4.)