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 A381813 #19 Mar 16 2025 12:19:50
%S A381813 3,2,1,7,2,5,8,8,6,50,12,30,61,62,47,417,102,303,682,696,532,4904,
%T A381813 1250,3854,8911,9218,7147,66735,17298,53965,126348,131740,103080
%N A381813 Number of connected components, not counting isolated vertices, of the blet graph for n coins.
%C A381813 The blet graph for n coins has one vertex for each binary heads/tails-sequence of length n. Two vertices are connected by an edge if there is a legal move between them in the game of blet, i.e., if one can be obtained from the other by replacing one occurrence of a triple THT with HTH. The binary sequences are circularly connected, so such a triple is allowed to start at one of the last two elements of the sequence and continue from the beginning.
%C A381813 The number of isolated vertices is A007039(n).
%C A381813 A075273(n) is the size of the component containing (HT)^n in the blet graph for 2*n coins.
%H A381813 Michael S. Branicky, <a href="/A381813/a381813.py.txt">Python program for OEIS A381813 and A381814</a>
%e A381813 For n = 4, the blet graph has A007039(4) = 6 isolated vertices TTTT, TTHH, THHT, HTTH, HHTT, HHHH, and a(4) = 2 components of size at least 2: {TTTH, THTT, THHH, HTHT, HHTH} and {TTHT, THTH, HTTT, HTHH, HHHT}.
%o A381813 (Python) # see linked program
%Y A381813 Cf. A007039, A075273, A381812, A381814 (size of the largest component).
%K A381813 nonn,more
%O A381813 3,1
%A A381813 _Pontus von Brömssen_, Mar 08 2025
%E A381813 a(24)-a(28) from _Michael S. Branicky_, Mar 08 2025
%E A381813 a(29)-a(30) from _Michael S. Branicky_, Mar 12 2025
%E A381813 a(31)-a(35) from _Bert Dobbelaere_, Mar 16 2025