A115869 - OEIS

A115869

Smallest natural number m < n, such that there exists nonzero solutions to a cross-domain congruence m*i = n X i, zero if no such integer exists.

0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 7, 0, 5, 6, 0, 0, 0, 0, 15, 0, 13, 14, 15, 0, 9, 10, 15, 12, 13, 0, 11, 0, 0, 0, 31, 0, 29, 30, 35, 0, 25, 26, 27, 28, 0, 30, 23, 0, 17, 18, 0, 20, 45, 30, 19, 24, 25, 26, 23, 0, 21, 22, 27, 0, 0, 0, 63, 0, 61, 62, 63, 0, 57, 58, 59, 60, 61, 70, 55, 0

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OFFSET

1,7

COMMENTS

Here * stands for ordinary multiplication and X means carryless (GF(2)[X]) multiplication (A048720).

LINKS

Table of n, a(n) for n=1..80.

Index entries for sequences defined by congruent products between domains N and GF(2)[X]

CROSSREFS

a(2n) = 2*a(n). Bisection A115870 gives the terms at odd positions. Differs from A115859 for the first time at n=23, where a(23)=15, while A115859(23)=19. Cf. A115857, A115861, A115871.

Sequence in context: A326128 A369931 A160086 * A115859 A241663 A344976

Adjacent sequences: A115866 A115867 A115868 * A115870 A115871 A115872

KEYWORD

nonn

AUTHOR

Antti Karttunen, Feb 07 2006

STATUS

approved