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A374269
a(n) is the smallest number which can be represented as the sum of n distinct positive n-th powers in exactly 4 ways, or -1 if no such number exists.
1
-1, 1105, 13896, 300834, 1386406515, 2063792939
OFFSET
1,2
EXAMPLE
a(2) = 1105 = 4^2 + 33^2 = 9^2 + 32^2 = 12^2 + 31^2 = 23^2 + 24^2.
a(3) = 13896 = 1^3 + 12^3 + 23^3 = 2^3 + 4^3 + 24^3 = 4^3 + 18^3 + 20^3 = 9^3 + 10^3 + 23^3.
CROSSREFS
KEYWORD
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AUTHOR
Ilya Gutkovskiy, Jul 02 2024
EXTENSIONS
a(6) from Michael S. Branicky, Jul 09 2024
STATUS
approved