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 A305429 #6 Jun 08 2018 13:53:10 %S A305429 1,1,2,3,3,5,5,7,7,7,7,11,11,13,13,13,13,17,17,19,19,19,19,23,23,25, %T A305429 25,25,25,29,29,31,31,31,31,31,31,37,37,37,37,41,41,43,43,43,43,47,47, %U A305429 47,47,47,47,53,53,55,55,55,55,59,59,61,61,61,61,61,61,67,67,69,69,71,71,73,73,73,73,77,77,79,79,81,81,83,83,83,83,87,87 %N A305429 Largest k < n whose binary expansion encodes an irreducible (0,1)-polynomial over Q, with a(1) = a(2) = 1. %C A305429 For n >= 3, a(n) is the largest term of A206074 less than n. %H A305429 Antti Karttunen, <a href="/A305429/b305429.txt">Table of n, a(n) for n = 1..21845</a> %o A305429 (PARI) %o A305429 A257000(n) = polisirreducible(Pol(binary(n))); %o A305429 A305429(n) = if(n<3,1, my(k=n-1); while(k>1 && !A257000(k),k--); (k)); %Y A305429 Cf. A206074, A257000, A305430. %Y A305429 Cf. also A151799 (A136548), A305419. %K A305429 nonn %O A305429 1,3 %A A305429 _Antti Karttunen_, Jun 07 2018