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 A357751 #14 Oct 13 2022 13:08:28
%S A357751 4,4,8,9,25,36,81,144,289,529,1089,2116,4225,8281,16641,33124,66049,
%T A357751 131769,263169,525625,1050625,2099601,4198401,8392609,16785409,
%U A357751 33558849,67125249,134235396,268468225,536895241,1073807361,2147488281,4295098369,8589953124,17180131329,34359812496
%N A357751 a(n) is the least perfect power > 2^n.
%H A357751 David A. Corneth, <a href="/A357751/b357751.txt">Table of n, a(n) for n = 0..3321</a>
%t A357751 pwQ[n_] := n == 1 || GCD @@ (Last /@ FactorInteger@n) > 1; a[n_] := Block[{t = 2^n + 1}, While[! pwQ@t, t++]; t]; a /@ Range[0, 30] (* _Giovanni Resta_, Oct 12 2022 *)
%o A357751 (PARI) for (n=0, 35, for (k=2^n+1, oo, if(ispower(k), print1(k,", "); break)))
%o A357751 (PARI) a(n) = { if(n < 2, return(4)); my(p2 = 1<<n, res = 1 << (n+1), c); forprime(i = 2, n + 1, c = (sqrtnint(p2, i)+1)^i; res = min(res, c); ); res } \\ _David A. Corneth_, Oct 12 2022
%Y A357751 Cf. A000079, A001597, A357752.
%K A357751 nonn,easy
%O A357751 0,1
%A A357751 _Hugo Pfoertner_, Oct 12 2022