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 A105076 Numbers k such that 60*k^2 + 60*k + 1 is a square. 0
 0, 1, 2, 11, 19, 90, 153, 712, 1208, 5609, 9514, 44163, 74907, 347698, 589745, 2737424, 4643056, 21551697, 36554706, 169676155, 287794595, 1335857546, 2265802057, 10517184216, 17838621864, 82801616185, 140443172858, 651895745267 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS FORMULA From R. J. Mathar, Nov 13 2009: (Start) a(n) = a(n-1) + 8*a(n-2) - 8*a(n-3) - a(n-4) + a(n-5). G.f.: x^2*(1+x+x^2)/((1-x)*(x^4-8*x^2+1)). (End) CROSSREFS Cf. A103200, A001090. Sequence in context: A067660 A235472 A217308 * A103200 A067670 A217071 Adjacent sequences:  A105073 A105074 A105075 * A105077 A105078 A105079 KEYWORD nonn AUTHOR Pierre CAMI, Apr 06 2005 EXTENSIONS Partially edited by Jon E. Schoenfield, Oct 13 2019 STATUS approved

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Last modified July 27 15:12 EDT 2021. Contains 346307 sequences. (Running on oeis4.)