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A216842
Degree of the smallest irreducible polynomial factor for the polynomial (x^(2n+1)+1)/(x+1) over GF(2).
0
0, 2, 4, 3, 2, 10, 12, 2, 8, 18, 2, 11, 4, 2, 28, 5, 2, 3, 36, 2, 20, 14, 2, 23, 3, 2, 52, 4, 2, 58, 60, 2, 4, 66, 2, 35, 9, 2, 3, 39, 2, 82, 4, 2, 11, 3, 2, 4, 48, 2, 100, 51, 2, 106, 36, 2, 28, 4, 2, 3, 10, 2, 4, 7, 2, 130, 3, 2, 68, 138, 2, 10, 4, 2, 148
OFFSET
0,2
MATHEMATICA
Join[{0}, Table[Exponent[FactorList[Sum[x^i, {i, 0, 2*n}], Modulus -> 2][[2, 1]], x], {n, 100}]] (* T. D. Noe, Sep 19 2012 *)
PROG
(PARI) vector(100, p, factormod((x^(2*p+1)+1)/(x+1), 2, 1)[1, 1])
CROSSREFS
Sequence in context: A084936 A365052 A308744 * A099066 A021415 A244646
KEYWORD
nonn
AUTHOR
V. Raman, Sep 17 2012
STATUS
approved