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 A079301 #24 Apr 22 2025 09:48:09 %S A079301 1,1,1,1,2,2,5,1,3,4,15,3,9,14,4,1,2,7,31,6,26,40,4,4,13,22,5,23,114, %T A079301 12,64,1,2,4,43,12,33,87,18,8,20,78,4,69,14,8,183,5,11,34,4,35,171,16, %U A079301 139,32,148,308,33,24,76,201,80,1,2,4,23,6,26,134,1014 %N A079301 a(n) = number of shortest addition chains for n that are Brauer chains. %C A079301 In a general addition chain, each element > 1 is a sum of two previous elements. In a Brauer chain, each element > 1 is a sum of the immediately previous element and another previous element. %H A079301 Glen Whitney, <a href="/A079301/b079301.txt">Table of n, a(n) for n = 1..18286</a> (Terms 1..1024 from D. W. Wilson) %H A079301 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/BrauerChain.html">Brauer Chain</a> %H A079301 Glen Whitney, <a href="/A079300/a079300.c.txt">C program to compute A079300</a>, also generates this sequence. %e A079301 All five of the shortest addition chains for 7 are Brauer chains: (1,2,3,4,7), (1,2,3,5,7), (1,2,3,6,7), (1,2,4,5,7), (1,2,4,6,7). Hence a(7) = 5. %e A079301 13 has ten shortest addition chains: (1,2,3,5,8,13), (1,2,3,5,10,13), (1,2,3,6,7,13), (1,2,3,6,12,13), (1,2,4,5,9,13), (1,2,4,6,7,13), (1,2,4,6,12,13), (1,2,4,8,9,13), (1,2,4,8,12,13), and (1,2,4,5,8,13). Of these, all but the last are Brauer chains. Hence a(13) = 9. %e A079301 12509 has 28 shortest addition chains, none of which are Brauer chains. Hence a(12509) = 0. %K A079301 nonn %O A079301 1,5 %A A079301 _David W. Wilson_, Feb 09 2003 %E A079301 Definition disambiguated by _Glen Whitney_, Nov 06 2021