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a(n) is the smallest number which can be represented as the sum of n distinct n-th powers of primes in exactly 3 ways, or -1 if no such number exists.
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%I #5 Jul 07 2024 21:05:31

%S -1,2210,8627527,616151524,876639080351

%N a(n) is the smallest number which can be represented as the sum of n distinct n-th powers of primes in exactly 3 ways, or -1 if no such number exists.

%e a(2) = 2210 = 19^2 + 43^2 = 23^2 + 41^2 = 29^2 + 37^2.

%e a(3) = 8627527 = 19^3 + 151^3 + 173^3 = 23^3 + 139^3 + 181^3 = 71^3 + 73^3 + 199^3.

%Y Cf. A349764, A374229, A374257, A374270, A374272.

%K sign,more

%O 1,2

%A _Ilya Gutkovskiy_, Jul 02 2024