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 A230697 #29 May 02 2025 12:12:38 %S A230697 0,1,2,2,3,3,4,3,3,4,4,4,5,5,4,3,4,4,5,4,5,5,6,4,4,5,4,5,5,5,6,4,5,5, %T A230697 5,4,5,5,5,5,6,5,6,6,5,6,6,5,5,5,6,6,6,5,6,6,6,6,7,5,6,6,6,4,5,5,6,5, %U A230697 6,6,7,5,6,6,5,6,6,6,7,5,4,5,5,5,6,6,6,6 %N A230697 Length of shortest addition-multiplication chain for n. %H A230697 Jinyuan Wang, <a href="/A230697/b230697.txt">Table of n, a(n) for n = 1..10000</a> %H A230697 H. M. Bahig, <a href="http://dx.doi.org/10.1016/j.disc.2007.04.015">On a generalization of addition chains: Addition-multiplication chains</a>, Discrete Mathematics 308 (2008), 611-616. %H A230697 Gleb Ivanov, <a href="/A230697/a230697.py.txt">Python program</a>. %e A230697 A shortest addition-multiplication chain for 16 is (1,2,4,16), of length a(16) = 3. %e A230697 A shortest addition-multiplication chain for 281 is (1,2,4,5,16,25,256,281), of length a(281) = 7. This is the first case where not all terms in some shortest chain are the sum or product of the immediately preceding term and one more preceding term. In other words, 281 is the smallest of the analog of non-Brauer numbers (A349044) for addition-multiplication chains. The next ones are 913, 941, 996, 997, 998, 1012, 1077, 1079, 1542, 1572, 1575, 1589, 1706, 1792, 1795, 1816, 1864, ... . - _Pontus von Brömssen_, May 02 2025 %Y A230697 Cf. A003313, A005245, A128998, A173419, A349044, A354914, A383001, A383002. %K A230697 nonn,nice %O A230697 1,3 %A A230697 _Harry Altman_, Oct 27 2013