OFFSET
1,1
COMMENTS
This is to 4th powers as A120398 is to cubes.
The first term that occurs in more than one way is a(1223) = 3262811042 = 7^4 + 239^4 = 157^4 + 227^4. - Robert Israel, Mar 12 2026
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
MAPLE
N:= 10^8: # for terms <= N
P:= select(isprime, [2, seq(i, i=3..floor(N^(1/4)))]): nP:= nops(P):
S:= select(`<=`, {seq(seq(P[i]^4 + P[j]^4, i=1..j-1), j=1..nP)}, N):
sort(convert(S, list)); # Robert Israel, Mar 12 2026
MATHEMATICA
Select[Sort[ Flatten[Table[Prime[n]^4 + Prime[k]^4, {n, 15}, {k, n - 1}]]], # <= Prime[15^4] &]
Total/@Subsets[Prime[Range[10]]^4, {2}]//Union (* Harvey P. Dale, Oct 20 2024 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Jonathan Vos Post, Jul 24 2007
STATUS
approved