OFFSET
1,1
EXAMPLE
1553= 1^4 + 4^4 + 6^4 = 1 + 256 + 1296.
6833 = 2^4 + 4^4 + 9^4 = 16 + 256 + 6561.
21377 = 2^4 + 5^4 + 12^4 = 16 + 625 + 20736.
35747 = 5^4 + 9^4 + 13^4 = 625 + 6561 + 28561.
MATHEMATICA
Union[Select[Total/@Subsets[Range[20]^4, {3}], PrimeQ]] (* Harvey P. Dale, May 08 2012 *)
PROG
(PARI) {m=15; p=m^4; v=vector(m, x, x^4); w=[]; for(i=1, m-2, for(j=i+1, m-1, for(k=j+1, m, if((n=v[i]+v[j]+v[k])<p&&isprime(n), w=concat(w, n))))); w=listsort(List(w), 1); for(j=1, #w-1, print1(w[j], ", "))} /* Klaus Brockhaus, Feb 11 2007 */
CROSSREFS
KEYWORD
nonn
AUTHOR
Tomas Xordan, Feb 09 2007
EXTENSIONS
Edited, corrected and extended by Klaus Brockhaus, Feb 11 2007
STATUS
approved