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 A376638 #10 Oct 03 2024 11:02:30 %S A376638 2,4,4,6,8,4,12,8,8,12,20,0,16,16,12,24,16,8,12,16,32,12,20,32,24,16, %T A376638 16,12,16,20,40,40,8,28,44,20,44,28,20,24,20,20,16,32,20,44,44,56,28, %U A376638 28,20,60,52,24,56,56,20,36,36,32,24,24,32,24,16,60,16,32 %N A376638 a(n) is the number of n-digit numbers in A376637. %C A376638 All terms are even: if a word w belongs to A376637, then replacing 1's by 2's and 2's by 1's in w yields another word in A376637. %C A376638 a(n)/2 is the number of terms of A376637 with digital sum n. %H A376638 Rémy Sigrist, <a href="/A376638/b376638.txt">Table of n, a(n) for n = 1..8192</a> %H A376638 Rémy Sigrist, <a href="/A376638/a376638.txt">C++ program</a> %H A376638 <a href="/index/K#Kolakoski">Index entries for sequences related to Kolakoski sequence</a> %e A376638 Sequence A376637 begins: 1, 2, 11, 12, 21, 22, 112, 122, 211, 221, 1121. %e A376638 So a(1) = 2, a(2) = 4, a(3) = 4. %o A376638 (C++) // See Links section. %Y A376638 Cf. A007782, A376637. %K A376638 nonn %O A376638 1,1 %A A376638 _Rémy Sigrist_, Sep 30 2024