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 A103166 #9 Dec 12 2021 19:47:43
%S A103166 0,0,0,13,23,46,53,140,215,105,210,2808,2918,15593,21187,63556,7987,
%T A103166 179118,358137,466945,420750,4034914,8068838,10946113,23445533,
%U A103166 46880176,22406063,117663950,219078635,1060248229,2021396468,2632727628,2954399858,13837158803
%N A103166 a(n) = reverse(2^n) mod 2^n.
%C A103166 Remainder if (2^n written backwards) is divided by 2^n.
%e A103166 a(4) = reverse(2^4) mod 2^4 = reverse(16) mod 16 = 61 mod 16 = 13.
%t A103166 Table[Mod[FromDigits[Reverse[IntegerDigits[2^n]]], 2^n], {n, 1, 256}]
%o A103166 (Python)
%o A103166 def a(n): t = 2**n; return int(str(t)[::-1])%t
%o A103166 print([a(n) for n in range(1, 35)]) # _Michael S. Branicky_, Dec 12 2021
%Y A103166 Cf. A002113, A071590, A103164-A103167.
%K A103166 base,nonn
%O A103166 1,4
%A A103166 _Labos Elemer_, Jan 28 2005