cp's OEIS Frontend

A025341 Numbers that are the sum of 3 distinct nonzero squares in exactly 3 ways.

%I A025341 #15 Jan 04 2016 04:49:29
%S A025341 101,110,126,134,146,149,173,174,182,185,186,221,222,237,245,251,257,
%T A025341 278,286,294,302,305,306,309,315,318,334,338,342,349,353,354,366,377,
%U A025341 402,404,409,410,430,440,453,454,467,481,490,502,504,514,515,517,526,529,531,536
%N A025341 Numbers that are the sum of 3 distinct nonzero squares in exactly 3 ways.
%H A025341 Robert Israel, <a href="/A025341/b025341.txt">Table of n, a(n) for n = 1..1690</a>
%H A025341 <a href="/index/Su#ssq">Index entries for sequences related to sums of squares</a>
%p A025341 N:= 10^6; # to get all terms <= N
%p A025341 A:= Vector(N):
%p A025341 for a from 1 to floor(sqrt(N/3)) do
%p A025341   for b from a+1 to floor(sqrt((N-a^2)/2)) do
%p A025341     c:= [$(b+1) .. floor(sqrt(N-a^2-b^2))]:
%p A025341     v:= map(t -> a^2 + b^2 + t^2, c):
%p A025341     A[v]:= map(`+`,A[v],1)
%p A025341 od od:
%p A025341 select(t -> A[t]=3,[$1..N]); # _Robert Israel_, Jan 03 2016
%K A025341 nonn
%O A025341 1,1
%A A025341 _David W. Wilson_