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 A233398 #13 Jan 11 2025 10:28:00
%S A233398 0,1,4,0,13,209,0,1231,739,0,51850,129587,0,657067,868120,0,8400886,
%T A233398 91426058,0,859535812,1483912651,0,30374372956,68688648677,0,
%U A233398 422259655777,2129293909882,0,11623487749588,44275834126985,0,329933248712302,971441847750184,0,927342285792613
%N A233398 n^n mod 3^n.
%C A233398 Conjecture: a(x) equals zero for every x that's a multiple of 3. - _Harvey P. Dale_, Jan 10 2025
%t A233398 Table[PowerMod[n,n,3^n],{n,0,40}] (* _Harvey P. Dale_, Jan 10 2025 *)
%o A233398 (Python)
%o A233398 for n in range(55): print(f"{n**n % 3**n}, ")
%Y A233398 Cf. A000244, A000312, A178537, A233397.
%K A233398 nonn
%O A233398 0,3
%A A233398 _Alex Ratushnyak_, Dec 08 2013