A374272 a(n) is the smallest number which can be represented as the sum of n distinct n-th powers of primes in exactly 4 ways, or -1 if no such number exists.
-1, 10370, 999979163, 199898912404
Offset: 1
Examples
a(2) = 10370 = 13^2 + 101^2 = 31^2 + 97^2 = 59^2 + 83^2 = 71^2 + 73^2. a(3) = 999979163 = 83^3 + 757^3 + 827^3 = 107^3 + 677^3 + 883^3 = 197^3 + 523^3 + 947^3 = 281^3 + 419^3 + 967^3.