

A290333


a(n) is the smallest k which satisfies (j^2 + k)/(j + k^2) = n where j,k are integers and j >= k > 0.


2



1, 3, 2, 4, 11, 27, 3, 12, 5, 31, 2, 95, 3, 495, 36, 7, 69, 8, 10, 231, 17, 8, 5, 80, 4, 3, 68, 47, 5, 11, 12, 23, 2147, 19, 6, 324, 4, 6107, 14, 31, 6585, 803, 12, 164, 14, 11, 5, 252, 75, 351, 8, 160, 17, 1317755, 19, 12, 50, 24, 2040, 5751, 5, 24255, 17, 1024, 521, 26847, 3
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OFFSET

1,2


LINKS

Zhining Yang, Table of n, a(n) for n = 1..300
Zhining Yang, Blog


EXAMPLE

a(5) = 11 since 5 = (27^2 + 11)/(27 + 11^2) and there is no integer k < 11 such that 5 = (j^2 + k)/(j + k^2) with j > k > 1.


PROG

(PARI) for(n=1, 100, for(b=1, 10^8, t=b*(b*n1); a=floor((n+sqrt(n*n+4*t))/2); if(a*(an)==t, print1(b, ", "); break)))


CROSSREFS

Cf. A290332.
Sequence in context: A277743 A296099 A319103 * A137824 A019321 A279261
Adjacent sequences: A290330 A290331 A290332 * A290334 A290335 A290336


KEYWORD

nonn


AUTHOR

Zhining Yang, Jul 27 2017


STATUS

approved



