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 A082651 Positive integer values of n such that 5n^2+11 is a square. 3
 1, 7, 25, 127, 449, 2279, 8057, 40895, 144577, 733831, 2594329, 13168063, 46553345, 236291303, 835365881, 4240075391, 14990032513, 76085065735, 268985219353, 1365291107839, 4826743915841, 24499154875367, 86612405265785, 439619496648767, 1554196550868289 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS The corresponding sequence for which 5n^2+4 is a square is A001906 (a bisection of the Fibonacci sequence). LINKS Colin Barker, Table of n, a(n) for n = 1..1000 Index entries for linear recurrences with constant coefficients, signature (0,18,0,-1). FORMULA a(n) = 18*a(n-2) - a(n-4). G.f.: x*(1+7*x+7*x^2+x^3)/(1-18*x^2+x^4). - Colin Barker, Jun 14 2012 EXAMPLE 25 is a term of the sequence since 5*25^2 + 11 = 56^2. PROG (PARI) Vec(x*(1+7*x+7*x^2+x^3)/(1-18*x^2+x^4) + O(x^100)) \\ Colin Barker, Nov 06 2014 CROSSREFS Cf. A001906, A080806. Sequence in context: A138292 A138738 A057573 * A241714 A151491 A208425 Adjacent sequences:  A082648 A082649 A082650 * A082652 A082653 A082654 KEYWORD nonn,easy AUTHOR John W. Layman, May 16 2003 EXTENSIONS More terms from Colin Barker, Nov 06 2014 STATUS approved

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Last modified January 23 10:49 EST 2022. Contains 350510 sequences. (Running on oeis4.)