cp's OEIS Frontend

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.

A268274 Numbers n such that x^n * (x+1)^(n-1) + 1 is irreducible over GF(2).

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%I A268274 #31 Dec 01 2022 17:20:53
%S A268274 1,2,3,4,5,8,21,32,33,36,53,64,85,89,148,312,404,3080,8380,11684,
%T A268274 16384,18089,21096,53492,78484,192248
%N A268274 Numbers n such that x^n * (x+1)^(n-1) + 1 is irreducible over GF(2).
%C A268274 Any subsequent terms are > 2 * 10^5. - _Lucas A. Brown_, Dec 01 2022
%o A268274 (Sage)
%o A268274 P.<x> = GF(2)[]
%o A268274 for n in range(1, 10^5):
%o A268274        if (x^n * (x+1)^(n-1) + 1).is_irreducible():
%o A268274            print(n)
%o A268274 (PARI) isok(n) = polisirreducible(Mod(1, 2)*x^n * (x+1)^(n-1) + 1); \\ _Michel Marcus_, Mar 03 2016
%Y A268274 Cf. A162570 (corresponding to powers of 2 in this sequence).
%K A268274 nonn,more,hard
%O A268274 1,2
%A A268274 _Joerg Arndt_, Mar 02 2016
%E A268274 a(26) from _Lucas A. Brown_, Dec 01 2022