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 A316866 #15 Aug 11 2018 14:08:36 %S A316866 0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0, %T A316866 0,1,0,0,0,0,0,0,0,0,0,1,0,0,0,0,1,1,1,1,1,2,1,1,1,1,0,0,0,0,0,1,0,0, %U A316866 0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0 %N A316866 Number of times 5 appears in decimal expansion of n. %e A316866 a(0) = 0 since the decimal representation of 0 does not contain the digit 5. %e A316866 a(5) = 1 since 5 appears once in the decimal expansion of 5. %t A316866 Array[ DigitCount[#, 10, 5] &, 105, 0] %o A316866 (PARI) a(n) = #select(x->x==5, digits(n)); \\ _Michel Marcus_, Jul 20 2018 %Y A316866 Cf. A043509, A043510, A043511, A043512. %Y A316866 Cf. A055641, A268643, A316863, A316864, A316865, A316867, A316868, A316869, A102683. %K A316866 base,easy,nonn %O A316866 0,56 %A A316866 _Robert G. Wilson v_, Jul 15 2018