1,3

Table of n, a(n) for n=1..97.

x=45, y=3, z=6. 45-9 = 36 = 6^2

(PARI) fourkp1(n) = { forstep(x=1, n, 4, for(y=1, floor(sqrt(x)), z=x-y^2; if(issquare(z), print1(y" "); break; ) ) ) }

Cf. A087819.

Sequence in context: A130784 A138034 A229216 * A112746 A107460 A152975

Adjacent sequences: A087815 A087816 A087817 * A087819 A087820 A087821

nonn

Cino Hilliard, Oct 06 2003

approved