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 A175190 #4 Jun 02 2025 02:47:32 %S A175190 0,1,1,1,2,1,1,2,1,2,2,3,2,3,1,2,3,2,4,3,2,1,3,2,3,4,2,1,2,1,3,4,3,2, %T A175190 2,3,2,3,3,4,3,2,2,3,4,1,3,2,3,4,4,3,4,3,3,4,3,4,6,1,2,3,1,6,5,2,2,3, %U A175190 4,3,5,4,5,4,4,3,4,3,5,6,3,6,4,3,4,3,5,4,5,2,2,3,4,3,3,2,3,2,2,3,6,3,5,4,3 %N A175190 Number of irreducible factors in the factorization of the polynomial x^n + x + 1 over the integers mod 2. %e A175190 the factorization of x^5+x+1 over integers mod 2 is (1+x^2+x^3)(1+x+x^2), which has two unique factors %p A175190 with(numtheory): for k from 1 to 200 do:liste:=Factors(x^k+ x +1) mod 2; t1 := liste[2]:t2 := (liste[2][i], i=1..nops(t1)):print(nops(t1)) ;od : %Y A175190 Cf. A000374 %K A175190 nonn %O A175190 1,5 %A A175190 _Michel Lagneau_, Mar 01 2010