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 A225106 #22 Jan 06 2025 21:53:06
%S A225106 9,25,81,125,512,5041
%N A225106 Prime powers (A025475) that can be represented as a sum of two distinct prime powers.
%C A225106 The next term, if it exists, is bigger than 2^64.
%C A225106 Conjecture: the sequence is finite. - _Alex Ratushnyak_, Feb 03 2020
%H A225106 Alex Ratushnyak, <a href="/A225106/a225106.txt">C program</a>
%e A225106 9 = 8 + 1.
%e A225106 25 = 16 + 9.
%e A225106 81 = 32 + 49.
%e A225106 125 = 121 + 4.
%e A225106 512 = 169 + 343.
%e A225106 5041 = 128 + 4913.
%t A225106 nn = 10000; p = Sort[Flatten[Table[Prime[n]^i, {n, PrimePi[Sqrt[nn]]}, {i, 2, Log[Prime[n], nn]}]]]; p = Join[{1}, p]; t = Union[Select[Flatten[Table[p[[i]] + p[[j]], {i, Length[p] - 1}, {j, i + 1, Length[p]}]], # <= nn &]]; Intersection[p, t] (* _T. D. Noe_, Apr 29 2013 *)
%o A225106 (C) /* See Ratushnyak link. */
%Y A225106 Cf. A025475, A331701.
%K A225106 nonn,hard,more
%O A225106 1,1
%A A225106 _Alex Ratushnyak_, Apr 28 2013