A084864 Numbers that can be written in the form 2*u^2 + 3*v^2, u*v>0.

5, 11, 14, 20, 21, 29, 30, 35, 44, 45, 50, 53, 56, 59, 62, 66, 75, 77, 80, 83, 84, 93, 98, 99, 101, 107, 110, 116, 120, 125, 126, 131, 140, 146, 147, 149, 155, 158, 165, 173, 174, 176, 179, 180, 189, 194, 197, 200, 203, 206, 210, 212, 219, 224, 227, 236, 237

Offset

1,1

Comments

A084863(a(n)) > 0; for primes see A084865, A084866.

Links

Jean-François Alcover, Table of n, a(n) for n = 1..10000

Example

30 = 18 + 12 = 2*3^2 + 3*2^2, therefore 30 is a term.

Mathematica

wmax = 240;
Table[w = 2 u^2 + 3 v^2; If[w <= wmax, w, Nothing], {u, 1, Sqrt[wmax/2] // Ceiling}, {v, 1, Sqrt[wmax/3] // Ceiling}] // Flatten // Union (* Jean-François Alcover, Dec 13 2021 *)

Crossrefs

Sequence in context: A313998 A174177 A256785 * A284396 A313999 A267298

Adjacent sequences: A084861 A084862 A084863 * A084865 A084866 A084867

Keyword

nonn

Author

Reinhard Zumkeller, Jun 10 2003

Status

approved