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.

A058943 Coefficients of irreducible polynomials over GF(2) listed in lexicographic order.

Original entry on oeis.org

10, 11, 111, 1011, 1101, 10011, 11001, 11111, 100101, 101001, 101111, 110111, 111011, 111101, 1000011, 1001001, 1010111, 1011011, 1100001, 1100111, 1101101, 1110011, 1110101, 10000011, 10001001, 10001111, 10010001
Offset: 1

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Author

N. J. A. Sloane, Jan 13 2001

Keywords

Comments

Church's table extends through degree 11.

Examples

			The first few are x, x+1; x^2+x+1; x^3+x+1, x^3+x^2+1; ... Note that x is irreducible but not primitive.
		

References

  • R. Lidl and H. Niederreiter, Finite Fields, Addison-Wesley, 1983, Table C, pp. 553-555.

Crossrefs

Converted to decimal: A014580.
Irreducible over GF(2), GF(3), GF(4), GF(5), GF(7): this sequence, A058944, A058948, A058945, A058946. Primitive irreducible over GF(2), GF(3), GF(4), GF(5), GF(7): A058947, A058949, A058952, A058950, A058951.

Programs

  • Mathematica
    Do[a = Reverse[ IntegerDigits[n, 2]]; b = {0}; l = Length[a]; k = 1; While[k < l + 1, b = Append[b, a[[k]]*x^(k - 1) ]; k++ ]; b = Apply[Plus, b]; c = Factor[b, Modulus -> 2]; If[b == c, Print[ FromDigits[ IntegerDigits[n, 2]]]], {n, 3, 250, 2} ]
  • PARI
    seq(N, p=2, maxdeg=oo) = {
      my(a = List(), k=0, d=0);
      while (d++ <= maxdeg,
        for (n=p^d, 2*p^d-1, my(f=Mod(Pol(digits(n,p)),p));
          if(polisirreducible(f), listput(a, subst(lift(f),'x,10)); k++);
          if(k >= N, break(2))));
      Vec(a);
    };
    seq(27) \\ Gheorghe Coserea, May 28 2018