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 A226786 #18 Mar 14 2023 11:45:38
%S A226786 0,0,2,0,2,0,1,0,8,0,7,0,5,0,2,0,15,0,12,0,8,0,3,0,22,0,17,0,11,0,4,0,
%T A226786 29,0,22,0,14,0,5,0,36,0,27,0,17,0,6,0,43,0,32,0,20,0,7,0,50,0,37,0,
%U A226786 23,0,8,0,57,0,42
%N A226786 If n=0 (mod 2) then a(n)=0, otherwise a(n)=8^(-1) in Z/nZ*.
%H A226786 Charles R Greathouse IV, <a href="/A226786/b226786.txt">Table of n, a(n) for n = 1..10000</a>
%F A226786 G.f.: -x^3*(x^14-x^10-3*x^8-8*x^6-x^4-2*x^2-2)/(x^16-2*x^8+1). - _Colin Barker_, Jun 20 2013
%t A226786 Inv[a_, mod_] := Which[mod == 1,0, GCD[a, mod] > 1, 0, True, Last@Reduce[a*x == 1, x, Modulus -> mod]];Table[Inv[8, n], {n, 1, 122}]
%t A226786 (* Second program: *)
%t A226786 Table[If[EvenQ[n], 0, ModularInverse[8, n], 0], {n, 1, 100}] (* _Jean-François Alcover_, Mar 14 2023 *)
%o A226786 (PARI) a(n)=if(n%2,lift(Mod(1,n)/8),0) \\ _Charles R Greathouse IV_, Jun 18 2013
%Y A226786 Cf. A092092, A226782-A226787.
%K A226786 nonn,easy
%O A226786 1,3
%A A226786 _José María Grau Ribas_, Jun 18 2013