A024804 Numbers that are the sum of 3 distinct nonzero squares in 2 or more ways.

62, 69, 74, 77, 86, 89, 90, 94, 98, 101, 105, 110, 117, 122, 125, 126, 129, 131, 134, 138, 141, 146, 149, 150, 154, 155, 158, 161, 165, 166, 170, 173, 174, 179, 181, 182, 185, 186, 189, 194, 195, 197, 201, 203, 206, 209, 210, 213, 217, 218, 221, 222, 225, 227, 229, 230

Offset: 1

Author

Clark Kimberling

Keywords

• nonn

Links

• Index entries for sequences related to sums of squares

Programs

Maple

isA024804 := proc(n) local ws; ws := 0 ; for x from 1 do if x^2 > n then break; end if; for y from x+1 do if x^2+y^2>n then break; end if; z := n-x^2-y^2 ; if issqr(z) then z := sqrt(z) ; if z > y then ws := ws+1 ; end if; end if ; end do: end do: ws >= 2 ; end proc:
for n from 1 to 230 do if isA024804(n) then printf("%d,",n) ; end if; end do: # R. J. Mathar, Dec 07 2010

Mathematica

nn=230; t=Table[0, {nn}]; Do[n=i^2+j^2+k^2; If[n<=nn, t[[n]]++], {i, Sqrt[nn]}, {j, i+1, Sqrt[nn]}, {k, j+1, Sqrt[nn]}]; Flatten[Position[t, _?(#>1&)]]

Formula

{n: A025442(n) >= 2}.