A066257 a(n) is the smallest number >1 of the form (k^2+n)/(n^2+k).

3, 2, 4, 3, 11, 16, 2, 29, 7, 5, 8, 67, 39, 92, 106, 11, 137, 34, 23, 191, 211, 8, 5, 277, 21, 3, 352, 165, 11, 10, 68, 37, 529, 83, 15, 31, 23, 704, 19, 315, 821, 67, 137, 63, 61, 28, 26, 7, 43, 1226, 931, 513, 87, 1432, 6, 23, 1597, 15, 1712, 1771, 13, 1892, 16, 11, 125

Offset

2,1

Comments

For n > 2, a(n) <= n^2/2 - 3*n^2/2 + 2, which is (k^2+n)/(n^2+k) for k = n^2 - 2*n + 2. - Robert Israel, Nov 18 2020

Links

Robert Israel, Table of n, a(n) for n = 2..2500

Maple

f:= proc(n) local S, m, k;
  S:= select(t -> subs(t, k) > n, [isolve(k^2+n=m*(n^2+k))]);
  min(map(t -> subs(t, m), S))
end proc:
map(f, [$2..100]); # Robert Israel, Nov 18 2020

Mathematica

Do[k = 1; While[m = (k^2 + n)/(n^2 + k); !IntegerQ[m] || m == 1, k++ ]; Print[m], {n, 2, 75} ]

Crossrefs

Cf. A066256.

Sequence in context: A243407 A061721 A294209 * A085591 A062964 A010270

Adjacent sequences: A066254 A066255 A066256 * A066258 A066259 A066260

Keyword

nonn,look

Author

Benoit Cloitre, Dec 31 2001

Extensions

More terms from Robert G. Wilson v, Jan 03 2002

Status

approved