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 A229076 Euler's fearsome foursome. 1
 18530, 38114, 45986, 65570 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Four distinct positive integers the sum of any two of which is a square, two of the squares being equal. Dunham calls them "Euler's fearsome foursome", but neglects to require that two of the sums be equal. Liu requires it and explains Euler's derivation. REFERENCES W. Dunham, Euler: The Master of Us All, MAA, 1999, p. 7. L. Euler, Opera Omnia, vol. 5, pp. 337 - 339, supplement to Paper 796. LINKS Paul Liu, The Elementary Mathematical Works of Leonhard Euler (1707 - 1783), pp. 129-133. EXAMPLE If (A, B, C, D) = (18530, 38114, 45986, 65570), then A+D = B+C = 290^2, A+C = 254^2, C+D = 334^2, A+B = 238^2, and B+D = 322^2. CROSSREFS Cf. A229077. Sequence in context: A237012 A031817 A236816 * A157740 A248488 A237700 Adjacent sequences:  A229073 A229074 A229075 * A229077 A229078 A229079 KEYWORD nonn,fini,full AUTHOR Jonathan Sondow, Sep 12 2013 STATUS approved

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Last modified December 2 16:17 EST 2021. Contains 349445 sequences. (Running on oeis4.)