The On-Line Encyclopedia of Integer Sequences (OEIS)

A091257 revision #11

A091257

Multiplication table A x B computed for polynomials over GF(2), where (A,B) runs as (1,1),(1,2),(2,1),(1,3),(2,2),(3,1),...

1, 2, 2, 3, 4, 3, 4, 6, 6, 4, 5, 8, 5, 8, 5, 6, 10, 12, 12, 10, 6, 7, 12, 15, 16, 15, 12, 7, 8, 14, 10, 20, 20, 10, 14, 8, 9, 16, 9, 24, 17, 24, 9, 16, 9, 10, 18, 24, 28, 30, 30, 28, 24, 18, 10, 11, 20, 27, 32, 27, 20, 27, 32, 27, 20, 11, 12, 22, 30, 36, 40, 18, 18, 40, 36, 30

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OFFSET

1,2

COMMENTS

Essentially same as A048720 but computed starting from offset one instead of zero. Analogous to A003991. Each n occurs A091220(n) times.

LINKS

Table of n, a(n) for n=1..76.

A. Karttunen, Scheme-program for computing this sequence.

Index entries for sequences operating on GF(2)[X]-polynomials

CROSSREFS

a(n) = A048720bi(A091255(n), A091256(n)) because the identity A x B = gcd(A, B) x lcm(A, B) holds also in the polynomial ring GF(2)[X].

Sequence in context: A308597 A205153 A300302 * * A216622 A319840

Adjacent sequences: A091254 A091255 A091256 * A091258 A091259 A091260

KEYWORD

nonn,tabl,changed

AUTHOR

Antti Karttunen, Jan 03 2004

STATUS

reviewed