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 A228914 Positive integers N such that 1/N = p/q - q/p + r/s - s/r for some positive integers p,q,r,s. 1
 4, 5, 9, 12, 15, 20, 21, 22, 24, 26, 29, 30, 31, 32, 34, 35, 36, 37, 38, 40, 43, 44, 53, 55, 56, 58, 59, 60, 62, 64, 66, 67, 68, 69, 70, 71, 74, 76, 77, 80, 82, 84, 86, 87, 88, 90, 91, 92, 94, 95, 102, 103, 104, 105, 106, 108, 109, 110, 112, 113, 115, 117, 122, 123, 129, 131, 132, 133, 135, 136, 137, 138, 139, 140, 141, 143, 144, 147 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Positive integer N belongs to this sequence if and only if the elliptic curve y^2 = x^3 + (8*N^2+1)*x^2 + 16*N^4*x has positive rank. LINKS PROG (PARI) { isA228914(n) = ellanalyticrank(ellinit([0, 8*n^2+1, 0, 16*n^4, 0]))[1]; } /* Max Alekseyev, Dec 30 2015 */ CROSSREFS Cf. A206334, A228380 Sequence in context: A126004 A258251 A184801 * A200535 A010405 A125603 Adjacent sequences:  A228911 A228912 A228913 * A228915 A228916 A228917 KEYWORD nonn AUTHOR Thomas Bokk, Sep 13 2013 EXTENSIONS More terms from Max Alekseyev, Sep 13 2013 STATUS approved

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Last modified June 17 15:07 EDT 2019. Contains 324185 sequences. (Running on oeis4.)