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 A145020 a(n) = ((7 + sqrt(7))^n - (7 - sqrt(7))^n)^2/28. 0
 1, 196, 23716, 2458624, 239754256, 22776846400, 2139058352704, 199857257119744, 18630079167234304, 1734834007938712576, 161472109634377851904, 15026063825688651366400 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Index entries for linear recurrences with constant coefficients, signature (154,-6468,74088). FORMULA From R. J. Mathar, Sep 30 2008: (Start) G.f.: x(1+42x)/((1-42x)(1-112x+1764x^2)). a(n) = 154*a(n-1) - 6468*a(n-2) + 74088*a(n-3). (End) PROG (MAGMA) Z:=PolynomialRing(Integers()); N:=NumberField(x^2-7); [ Integers()!a: a in [ ((7+r7)^n-(7-r7)^n)^2/28: n in [1..12] ] ]; // Klaus Brockhaus, Oct 20 2008 CROSSREFS Sequence in context: A035834 A114761 A076002 * A333641 A260863 A013755 Adjacent sequences:  A145017 A145018 A145019 * A145021 A145022 A145023 KEYWORD nonn,easy AUTHOR Al Hakanson (hawkuu(AT)gmail.com), Sep 29 2008 EXTENSIONS Extended by R. J. Mathar, Sep 30 2008 STATUS approved

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Last modified May 16 23:46 EDT 2021. Contains 343957 sequences. (Running on oeis4.)