A228914 Positive integers N such that 1/N = p/q - q/p + r/s - s/r for some positive integers p,q,r,s.

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

Offset: 1

Author

Thomas Bokk, Sep 13 2013

Keywords

• nonn

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.

Crossrefs

Cf. A206334, A228380

Programs

PARI

{ isA228914(n) = ellanalyticrank(ellinit([0, 8*n^2+1, 0, 16*n^4, 0]))[1]; } /* Max Alekseyev, Dec 30 2015 */

Extensions

More terms from Max Alekseyev, Sep 13 2013