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 A110471 #15 Sep 11 2024 14:15:24 %S A110471 1,1,1,1,0,1,1,1,0,0,1,1,0,1,1,1,1,0,0,0,0,1,1,1,0,0,1,1,0,1,1,1,0,1, %T A110471 0,0,0,0,0,0,0,0,1,1,0,1,1,1,1,0,0,0,0,1,1,1,0,0,1,1,0,1,1,1,1,0,1,1, %U A110471 0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,1,1,1,0,0,1,1,0,1,1,1,0,1,0,0,0,0,0,0,0 %N A110471 Prime analog of Baum-Sweet sequence: a(n) = 1 if binary representation of n contains no block of consecutive zeros of exactly prime length; otherwise a(n) = 0. %D A110471 J.-P. Allouche and J. Shallit, Automatic Sequences, Cambridge Univ. Press, 2003, p. 157. %H A110471 J.-P. Allouche, <a href="http://www.mat.univie.ac.at/~slc/s/s30allouche.html">Finite Automata and Arithmetic</a>, Séminaire Lotharingien de Combinatoire, B30c (1993), 23 pp. %e A110471 a(4) = 0 because 4 (base 2) = 100, which has 2 (prime) consecutive zeros. %e A110471 a(8) = 0 because 8 (base 2) = 1000, which has 3 (prime) consecutive zeros. %e A110471 a(9) = 0 because 9 (base 2) = 1001, which has 2 (prime) consecutive zeros. %e A110471 a(16) = 1 because 16 (base 2) = 10000, which has 4 (composite) consecutive zeros, even though there are subblocks of zeros of lengths 2 and 3. %e A110471 a(32) = 0 because 32 (base 2) = 100000, which has 5 (prime) consecutive zeros. %t A110471 f[n_] := If[Or @@ (First[ # ] == 0 && PrimeQ[Length[ # ]] &) /@ Split[IntegerDigits[n, 2]], 0, 1]; Table[f[n], {n, 0, 120}] (* _Ray Chandler_, Sep 16 2005 *) %Y A110471 Cf. A037011, A086747, A110472, A110474. %K A110471 base,easy,nonn %O A110471 0,1 %A A110471 _Jonathan Vos Post_, Sep 07 2005 %E A110471 Extended by _Ray Chandler_, Sep 16 2005