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

1,1

Links

Table of n, a(n) for n=1..56.

Index entries for sequences related to sums of squares

Formula

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

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&)]]

Crossrefs

Sequence in context: A095577 A095565 A095553 * A025340 A048127 A047823

Adjacent sequences: A024801 A024802 A024803 * A024805 A024806 A024807

Keyword

nonn

Author

Clark Kimberling

Status

approved