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 A339555 #10 Feb 16 2025 08:34:01
%S A339555 1,1,1,1,3,3,5,5,11,25,41,41,80,80,144,284,568,568,1147,1147,2339,
%T A339555 4667,8763,8763,17548,35196,67964,135918,273806,273806,548956,548956,
%U A339555 1097974,2194294,4291446,8608698,17216783,17216783,33993999,67979983,135956742
%N A339555 Number of subsets of {2..n} such that the product of the elements is a perfect power.
%H A339555 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PerfectPower.html">Perfect Power</a>
%F A339555 a(p) = a(p-1) for p prime.
%e A339555 a(8) = 11 subsets: {}, {4}, {8}, {2, 4}, {2, 8}, {4, 8}, {2, 3, 6}, {2, 4, 8}, {3, 6, 8}, {2, 3, 4, 6} and {3, 4, 6, 8}.
%Y A339555 Cf. A001597, A089819, A320322, A339554.
%K A339555 nonn
%O A339555 0,5
%A A339555 _Ilya Gutkovskiy_, Dec 08 2020
%E A339555 a(25)-a(40) from _Alois P. Heinz_, Dec 08 2020