A128901 - OEIS

A128901

Number of degree n polynomials over GF(2) (with nonzero constant term) at Hamming distance 1 from some irreducible polynomial.

0, 1, 2, 4, 8, 16, 32, 63, 128, 255, 510, 1020, 2032, 4048, 8109, 16216, 32434, 64731, 129597, 258718, 517424, 1034430, 2067780, 4132038, 8262934, 16515320, 33021972, 66029987, 132008983, 263944002, 527772375, 1055126462

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OFFSET

1,3

LINKS

Table of n, a(n) for n=1..32.

G. Lee, F. Ruskey and A. Williams, Hamming distance from irreducible polynomials over GF(2)

EXAMPLE

The coefficient vectors of the two degree 3 irreducible polynomials are 1011 and 1101. They are at distance one from the two polynomials 1001 and 1111; thus a(3) = |{1001,1111}| = 2.

CROSSREFS

Sequence in context: A140134 A243084 A049886 * A025489 A160686 A201920

Adjacent sequences: A128898 A128899 A128900 * A128902 A128903 A128904

KEYWORD

nonn

AUTHOR

Frank Ruskey, Apr 22 2007

STATUS

approved