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 A383337 #9 May 02 2025 12:11:50 %S A383337 1,1,2,7,45,485 %N A383337 Number of integers with a shortest addition-multiplication-exponentiation chain of length n. %e A383337 Only 1 has an addition-multiplication-exponentiation chain of length 0, so a(0) = 1. %e A383337 Only 2 has a shortest chain of length 1, so a(1) = 1. %e A383337 3 and 4 have shortest chains of length 2, so a(2) = 2. %e A383337 5, 6, 8, 9, 16, 27, and 256 have shortest chains of length 3, so a(3) = 7. %Y A383337 Cf. A003065, A383002, A383143, A383335, A383336. %K A383337 nonn,hard,more %O A383337 0,3 %A A383337 _Pontus von Brömssen_, Apr 27 2025