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 A383143 #9 Apr 18 2025 10:59:33 %S A383143 1,1,2,3,5,9,16,28,49,88,156,280,499,904,1639,2986,5442,9936,18134 %N A383143 Number of positive integers with a shortest addition-subtraction chain of length n. %H A383143 Neill Clift, <a href="http://additionchains.com/AdditionSubtraction.html">Addition Subtraction Chains</a>. %H A383143 <a href="/index/Com#complexity">Index to sequences related to the complexity of n</a> %F A383143 a(n) >= A003065(n). %e A383143 a(6) = 16 because the number of occurrences of 6 in A128998 is 16. These numbers are 19, 21, 22, 23, 25, 26, 27, 28, 30, 31, 33, 34, 36, 40, 48, 64. %Y A383143 Cf. A003065, A128998, A383002, A383142. %K A383143 nonn,hard,more %O A383143 0,3 %A A383143 _Jinyuan Wang_, Apr 17 2025