A224772 Multiplicities for representations of numbers as primitive sums of three distinct nonzero squares.

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 0, 1, 0, 1, 2, 0, 0, 1, 1, 0, 0, 2, 1, 0, 0, 0, 2, 1, 0, 2, 1, 0, 0, 1, 0, 1, 0, 0, 2, 0, 0, 2, 2, 1, 0, 1, 2, 0, 0, 0, 2, 0, 0, 3, 0, 0, 0, 2, 1, 1, 0, 1, 3, 0, 0, 1, 1, 1, 0, 2, 1, 0, 0, 1, 2, 0, 0, 2, 2, 0, 0, 2, 0, 2, 0, 1, 3, 0, 0, 1, 2, 1, 0, 2

Offset: 1

Author

Wolfdieter Lang, Apr 19 2013

Keywords

• nonn

Comments

a(n) = k, for n >= 1, if there are exactly k representations of n as a primitive sum of three distinct nonzero squares. If a(n) = 0 then n has no such representation.

The increasingly ordered numbers with a(n) > 0 are given in A224771.

Examples

			a(14) = 1 because the first number with a representation in question, denoted by a triple (a, b, c), is 14, with the unique triple (1, 2, 3).
a(62) = 2 for the first number 62 which has two representations, denoted by (1, 5, 6) and (2, 3, 7).
a(101) = 3 for the first number 101 with three triples, namely (1, 6, 8), (2, 4, 9) and (4, 6, 7).
		

Links

• T. D. Noe, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A224771, A025442 (multiplicities for sums of three distinct nonzero squares).

Programs

Mathematica

nn = 10; t = Table[0, {nn^2}]; Do[If[GCD[a, b, c] == 1, n = a^2 + b^2 + c^2; If[n <= nn^2, t[[n]]++]], {a, nn}, {b, a + 1, nn}, {c, b + 1, nn}]; t (* T. D. Noe, Apr 20 2013 *)

Formula

a(n) = k if n = a^2 + b^2 + c^2, a, b, and c integers, 0 < a < b < c and gcd(a,b,c) = 1, for exactly k different triples (a, b, c). If there is no such triple then a(n) = 0.