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 A030064 1 + product of any two terms is a square. 0
 0, 2, 4, 12, 420 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 REFERENCES Martin Gardner, probably "Mathematical Magic Show". LINKS Table of n, a(n) for n=1..5. A. Baker and H. Davenport, The Equations 3x^2-2=y^2 and 8x^2-7=z^2, Quart. J. Math. Oxford 20 (1969). EXAMPLE 0*2,4,12,420 + 1 = 1 2*4 + 1 = 9 2*12 + 1 = 25 2*420 + 1 = 841 -> sqrt = 29 4*12 + 1 = 49 4*420 + 1 = 1681 -> sqrt = 41 12*420 + 1 = 5041 -> sqrt = 71 CROSSREFS Sequence in context: A291827 A287059 A059085 * A224886 A180500 A176990 Adjacent sequences: A030061 A030062 A030063 * A030065 A030066 A030067 KEYWORD nonn,fini,full AUTHOR Timothy Chow (tchow(AT)math.lsa.umich.edu) EXTENSIONS Corrected by Mitch Harris, Apr 24 2006 STATUS approved

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Last modified December 1 05:26 EST 2023. Contains 367468 sequences. (Running on oeis4.)