This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A374257 #15 Jul 09 2024 19:10:34 %S A374257 -1,325,5104,16578,70211956,201968338,1690592199245 %N A374257 a(n) is the smallest number which can be represented as the sum of n distinct positive n-th powers in exactly 3 ways, or -1 if no such number exists. %e A374257 a(2) = 325 = 1^2 + 18^2 = 6^2 + 17^2 = 10^2 + 15^2. %e A374257 a(3) = 5104 = 1^3 + 12^3 + 15^3 = 2^3 + 10^3 + 16^3 = 9^3 + 10^3 + 15^3. %o A374257 (Python) %o A374257 from itertools import count %o A374257 from sympy.solvers.diophantine.diophantine import power_representation %o A374257 def A374257(n): return next(m for m in count(1) if len(list(power_representation(m,n,n)))==3) if n>1 else -1 # _Chai Wah Wu_, Jul 01 2024 %Y A374257 Cf. A025304, A025401, A146756, A374227, A374256. %K A374257 sign,more %O A374257 1,2 %A A374257 _Ilya Gutkovskiy_, Jul 01 2024 %E A374257 a(7) from _Michael S. Branicky_, Jul 09 2024