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 A291781 #14 Jul 12 2018 08:08:24 %S A291781 0,0,4,12,16,32,64,128,384,704,896,2304,4608,7680,16384,36864,65536, %T A291781 143360,303104,565248,1245184,2473984,4521984,9961472,19070976, %U A291781 35389440,78643200,154664960,289931264,635437056,1309671424,2503999488,5280628736 %N A291781 Consider the Watanabe tag system defined in A291067; a(n) = number of binary words of length n which terminate in a cycle. %H A291781 Don Reble, <a href="/A291781/b291781.txt">Table of n, a(n) for n = 1..60</a> %Y A291781 Cf. A284116, A291067, A291780. %K A291781 nonn %O A291781 1,3 %A A291781 _Don Reble_ and _N. J. A. Sloane_, Sep 01 2017