A047801 - OEIS

%I #22 Sep 27 2023 09:13:22

%S 1,5,14,29,50,74,111,149,197,247,308,370,451,526,613,706,815,914,1037,

%T 1146,1284,1416,1565,1698,1876,2030,2209,2380,2578,2757,2972,3168,

%U 3401,3612,3850,4071,4339,4575,4843,5089,5388

%N Number of different values of i^2+j^2+k^2+l^2 for i,j,k,l in [ 0,n ].

%H Robin Visser, <a href="/A047801/b047801.txt">Table of n, a(n) for n = 0..5000</a> (terms n = 0..100 from T. D. Noe).

%t Table[ Length@Union@Flatten@Table[ i^2+j^2+k^2+l^2, {i, 0, n}, {j, i, n}, {k, j, n}, {l, k, n} ], {n, 0, 48} ]

%Y Cf. A034966, A047800.

%Y Partial sums of A122927.

%K nonn,easy,nice

%O 0,2

%A _Wouter Meeussen_

%E Definition corrected by _Jonathan Vos Post_, Nov 14 2007