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 A123399 #11 Apr 28 2012 05:49:26
%S A123399 1,2,3,5,6,9,11,14,23,26,29,30,33,35,39,41,51,53,65,69,74,81,83,86,89,
%T A123399 90,95,105,113,119,131,135,146,155,158,173,179,183,189,191,209,210,
%U A123399 221,230,231,233,239,243,245,251,254,261,273,281,293,299,303,306,309,323,326,329,330,359,371,375,386,398,411,413,419
%N A123399 Orders of "Gray" fields.
%C A123399 Numbers n such that there is a type-2 optimal normal basis over GF(2) and the corresponding polynomial is primitive. Subsequence of A054639. [_Joerg Arndt_, Apr 28 2012]
%D A123399 D. E. Knuth, The Art of Computer Programming, Section 7.2.1.1, Problem 31.
%H A123399 Joerg Arndt, <a href="/A123399/b123399.txt">Table of n, a(n) for n = 1..133</a>
%F A123399 Let c_1(x) = x+1, c_2(x) = x^2+x+1, c_{j+1}(x) = x*c_j(x) + c_{j-1}(x) be polynomials over GF(2). Then n is in the sequence iff c_n(x) is a primitive irreducible polynomial.
%Y A123399 Cf. A054639.
%K A123399 nonn
%O A123399 1,2
%A A123399 _N. J. A. Sloane_, Oct 15 2006
%E A123399 Terms >=105 by _Joerg Arndt_, Apr 28 2012.