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 A362769 #39 Aug 26 2025 21:25:55 %S A362769 1,1,1,1,1,1,1,1,1,6,7,4,4,4,3,5,5,4,3,5,6,6,4,3,2,4,4,4,4,3,4,3,4,4, %T A362769 4,2,4,4,4,5,5,5,4,5,3,4,5,3,4,3,4,4,4,4,4,4,4,4,4,5,5,3,4,3,4,4,5,5, %U A362769 4,5,5,5,4,4,4,6,6,4,4,4,4,4,5,5,4,5,5,5,3,3,4,4,4,4,4,4,4,4,4,8,9 %N A362769 Minimum number of digits required to represent n only using digits present in n. %C A362769 The only operations allowed are addition, subtraction, multiplication, division, exponentiation, and parenthesizing. Concatenation is not allowed. %C A362769 Real and imaginary intermediate values are allowed as long as the final value of the expression is an integer. - _Walter Robinson_, Aug 22 2025 %H A362769 Valentin Miakinen, <a href="https://github.com/RedStorm1024/MPDR-Bruteforcer/blob/main/btdmathchallenge.py">Python program</a> %e A362769 For n = 10, a solution for a(10)=6 is (1+1+1)^(1+1)+1. %e A362769 For n = 27, a solution for a(27)=4 is 2+(2-7)^2. %o A362769 (Python) # See Miakinen link. %Y A362769 Cf. A043537. %K A362769 nonn,base,changed %O A362769 1,10 %A A362769 _Oskar Macholl_, Valentin Miakinen, and _Walter Robinson_, May 02 2023 %E A362769 Edited by _N. J. A. Sloane_, Oct 16 2023.