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 A374425 #8 Jul 16 2024 16:14:45 %S A374425 13,78,1521,16578,1479604544,1885800643779 %N A374425 a(n) is the smallest number which can be represented as the sum of 4 distinct positive n-th powers in exactly 3 ways, or -1 if no such number exists. %e A374425 a(4) = 16578 = 1^4 + 2^4 + 9^4 + 10^4 = 2^4 + 5^4 + 6^4 + 11^4 = 3^4 + 7^4 + 8^4 + 10^4. %e A374425 a(5) = 1479604544 = 3^5 + 48^5 + 52^5 + 61^5 = 13^5 + 36^5 + 51^5 + 64^5 = 18^5 + 36^5 + 44^5 + 66^5. %Y A374425 Cf. A046881, A374418, A374421, A374422, A374423, A374424. %K A374425 nonn,hard,more %O A374425 1,1 %A A374425 _Ilya Gutkovskiy_, Jul 08 2024 %E A374425 a(6) from _Michael S. Branicky_, Jul 09 2024