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 A057496 #23 May 11 2021 09:45:55 %S A057496 1,2,3,4,5,7,10,17,20,25,28,31,41,52,130,151,196,503,650,761,986,1391, %T A057496 2047,6172,6431,6730,8425,10162,11410,12071,13151,14636,17377,18023, %U A057496 32770,77047,102842,130777,137113,143503,168812,192076 %N A057496 Numbers n such that x^n + x^3 + x^2 + x + 1 is irreducible over GF(2). %C A057496 If x^n + x^3 + x^2 + x + 1 is irreducible, then so is its "twin" x^n + x^3 + 1. - Gove Effinger, Mar 11 2007 %C A057496 No term other than 3 can be a multiple of 3, since for m > 1, x^(3*m) + x^3 + x^2 + x + 1 is divisible by x^2 + x + 1. - _Jianing Song_, May 11 2021 %F A057496 Using probabilistic arguments it appears that there should be about 6.5 terms in this sequence with any given number of decimal digits d. - Gove Effinger, Mar 11 2007 %Y A057496 Cf. A002475. %Y A057496 Other than the term 3, subsequence of A057461. %K A057496 nonn %O A057496 1,2 %A A057496 _Robert G. Wilson v_, Sep 27 2000 %E A057496 a(20)-a(23) from _Robert G. Wilson v_, Mar 11 2007 %E A057496 a(24)-a(27) computed by _Richard P. Brent_, Mar 11 2007, communicated by Gove Effinger %E A057496 a(27)-a(35) computed by _Richard P. Brent_, Mar 16 2007, communicated by Gove Effinger %E A057496 a(36)-a(42) computed by Jonathan Webster, Feb 18 2010 %E A057496 Added entries a(1), a(2), a(3) since x^3 + x^2 + 1, x^3 + x + 1 and x^2 + x + 1 are irreducible over GF(2). Changed the offset for the entries computed by _Robert G. Wilson v_ and _Richard P. Brent_ to account for this. Added terms a(36) through a(42). - Jonathan Webster (jwebster(AT)bates.edu), Feb 18 2010