

A087671


Number of subsets S of {0,1,2,...,n1} which are idempotent under squaring modulo n, where S*S mod n = {x*y mod nx,y in S}.


0



2, 4, 6, 8, 8, 27, 10, 26, 18, 43, 10, 146, 14, 59, 107, 114, 12, 184, 14, 406, 142, 59
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OFFSET

1,1


LINKS

Table of n, a(n) for n=1..22.


EXAMPLE

{4} is one of the a(6)=27 idempotent (mod 6) subsets of {0,1,2,3,4,5}, since {4}*{4}={16 mod 6}={4}.


CROSSREFS

Sequence in context: A219028 A333557 A062355 * A088308 A167832 A134488
Adjacent sequences: A087668 A087669 A087670 * A087672 A087673 A087674


KEYWORD

nonn,more


AUTHOR

John W. Layman, Sep 26 2003


STATUS

approved



