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 A147771 #13 Feb 17 2020 10:51:25
%S A147771 1,2,5,16,56,216,907,4096,19683,100000,534146,2985984,17403307,
%T A147771 105413504,661735514,4294967296,28761784748,198359290368,
%U A147771 1406563064942,10240000000000,76436817165460,584318301411328,4569515072723572
%N A147771 a(n) = round(n^(n/2)).
%H A147771 Chai Wah Wu, <a href="/A147771/b147771.txt">Table of n, a(n) for n = 1..500</a>
%t A147771 lst={};Do[AppendTo[lst,Round[(n^n)^(1/2)]],{n,40}];lst
%t A147771 Table[Round[n^(n/2)],{n,30}] (* _Harvey P. Dale_, Feb 17 2020 *)
%o A147771 (Python)
%o A147771 from gmpy2 import isqrt_rem
%o A147771 def A147771(n):
%o A147771 i, j = isqrt_rem(n**n)
%o A147771 return int(i+int(4*(j-i) >= 1)) # _Chai Wah Wu_, Aug 16 2016
%Y A147771 Cf. A075364, A066642.
%K A147771 nonn
%O A147771 1,2
%A A147771 _Vladimir Joseph Stephan Orlovsky_, Nov 12 2008