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 A305214 #15 May 22 2020 05:50:56 %S A305214 7,9,14,18,21,27,28,35,36,42,45,49,54,56,63,70,72,77,81,84,90,91,98, %T A305214 99,105,108,112,117,119,126,133,135,140,144,147,153,154,161,162,168, %U A305214 171,175,180,182,189,196,198,203,207,210,216,217,224,225,231,234,238 %N A305214 Numbers k such that A305212(k) is not zero. %C A305214 Conjecture: These are simply the positive integers that are divisible by 7 or 9. %o A305214 (Python) [n for n in range(100) if n != len(set((pow(x,3,n) + pow(y,3,n))%n for x in range(n) for y in range(n)))] %o A305214 (PARI) isok(n) = my(v=[]); for (x=1, n, for (y=1, n, v = concat(v, Mod(x, n)^3 + Mod(y, n)^3))); n != #Set(v); \\ _Michel Marcus_, Jul 10 2018 %Y A305214 Cf. A305211, A305212. %K A305214 nonn %O A305214 1,1 %A A305214 _Jack Zhang_, May 27 2018 %E A305214 a(25)-a(57) from _Jon E. Schoenfield_, May 28 2018