A121278 - OEIS

%I #9 Oct 16 2023 04:31:08

%S 1,3,5,3,13,9,19,5,15,15,51,9,73,30,65,9,113,21,163,9,25,63,265,15,65,

%T 57,45,30,281,45,391,17,255,123,247,21,577,165,65,15,841,27,757,63,

%U 195,234,1105,27,133,75,565,30,1249,57,65,50,95,339,929,27,1321,408,75,33,949

%N Number of distinct integers of the form (x^n + y^n) mod n^2.

%C It is enough to take x,y from {0,1,...,n-1}. Therefore a(n)<=n*(n+1)/2.

%o (PARI) { a(n) = my(S, t); S=Set(); for(x=0,n-1, for(y=x,n-1, t=lift(Mod(x,n^2)^n+Mod(y,n^2)^n); S=setunion(S,[t]); ); ); #S }

%o (PARI) a(n) = #setbinop((x, y)->Mod(x, n^2)^n+Mod(y, n^2)^n, [0..n-1]); \\ _Michel Marcus_, Oct 16 2023

%K nonn

%O 1,2

%A _Max Alekseyev_, Aug 23 2006

%E More terms from _Michel Marcus_, Oct 16 2023