A065461 - OEIS

%I #15 Sep 08 2020 19:55:00

%S 1,1,2,3,4,7,10,13,16,27,36,43,58,72,99,130,146,178,254,265,342,417,

%T 507,540,726,745,975,1092,1289,1338,1845,1751,2246,2447,2948,2852,

%U 3932,3638,4728,4868,5778,5618,7659,6887,8891,8887,10825,10109,13712

%N Number of inequivalent (ordered) solutions to n^2 = sum of 7 squares of integers >= 0.

%H Alois P. Heinz, <a href="/A065461/b065461.txt">Table of n, a(n) for n = 0..500</a>

%e a(4)=4 because 16 produces {0,0,0,0,0,0,4}, {0,0,0,2,2,2,2}, {0,0,1,1,1,2,3}, {1,1,1,1,2,2,2}.

%t Table[Length[PowersRepresentations[n^2,7,2]],{n,0,50}] (* _Harvey P. Dale_, Sep 08 2020 *)

%Y Cf. A063014, A016727.

%Y Column k=7 of A255212.

%K nonn

%O 0,3

%A _Wouter Meeussen_, Nov 18 2001

%E a(0)=1 prepended by _Alois P. Heinz_, Feb 17 2015

%E Previous Mathematica program replaced by _Harvey P. Dale_, Sep 08 2020