A124966 - OEIS

A124966

Numbers which can be expressed as the ordered sum of 3 squares in 2 or more different ways.

9, 17, 18, 25, 26, 27, 29, 33, 34, 36, 38, 41, 45, 49, 50, 51, 53, 54, 57, 59, 61, 62, 65, 66, 68, 69, 72, 73, 74, 75, 77, 81, 82, 83, 85, 86, 89, 90, 94, 97, 98, 99, 100, 101, 102, 104, 105, 106, 107, 108, 109, 110, 113, 114, 116, 117, 118, 121, 122, 123, 125, 126, 129

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Robert Price, Table of n, a(n) for n = 1..83131

FORMULA

Equals = A000027 - A094942 - A004215.

EXAMPLE

a(1)=9 because 9 = 3^2 + 0^2 + 0^2 or 2^2 + 2^2 + 1^2.

MATHEMATICA

Select[Range[129], Length@PowersRepresentations[#, 3, 2] >= 2 &] (* Ray Chandler, Oct 31 2019 *)

CROSSREFS