OFFSET
1,1
LINKS
Robert Israel, Table of n, a(n) for n = 1..4500
EXAMPLE
MAPLE
N:= 2*10^4: # for terms <= N
V:= Vector(N):
for j from 1 while 2*j^4 < N do
for k from j+1 do
r:= j^4 + k^4;
if r > N then break fi;
V[r]:= V[r]+1;
od od:
select(t -> V[t] = 1, [$1..N]); $ Robert Israel, Dec 15 2019
MATHEMATICA
lst={}; Do[Do[x=a^4; Do[y=b^4; If[x+y==n, AppendTo[lst, n]], {b, Floor[(n-x)^(1/4)], a+1, -1}], {a, Floor[n^(1/4)], 1, -1}], {n, 4*7!}]; lst (* Vladimir Joseph Stephan Orlovsky, Jan 22 2009 *)
PROG
(PARI) powers2(m1, m2, p1) = { for(k=m1, m2, a=powers(k, p1); if(a==1, print1(k", ")) ); } powers(n, p) = { z1=0; z2=0; c=0; cr = floor(n^(1/p)+1); for(x=1, cr, for(y=x+1, cr, z1=x^p+y^p; if(z1 == n, c++); ); ); return(c) }
CROSSREFS
KEYWORD
nonn
AUTHOR
Cino Hilliard, Nov 22 2003
EXTENSIONS
Edited by Don Reble, May 03 2006
STATUS
approved