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A060839 Number of non-congruent solutions of x^3 == 1 mod n. +0
5
1, 1, 1, 1, 1, 1, 3, 1, 3, 1, 1, 1, 3, 3, 1, 1, 1, 3, 3, 1, 3, 1, 1, 1, 1, 3, 3, 3, 1, 1, 3, 1, 1, 1, 3, 3, 3, 3, 3, 1, 1, 3, 3, 1, 3, 1, 1, 1, 3, 1, 1, 3, 1, 3, 1, 3, 3, 1, 1, 1, 3, 3, 9, 1, 3, 1, 3, 1, 1, 3, 1, 3, 3, 3, 1, 3, 3, 3, 3, 1, 3, 1, 1, 3, 1, 3, 1, 1, 1, 3, 9, 1, 3, 1, 3, 1, 3, 3, 3, 1, 1, 1, 3, 3, 3 (list; graph; listen)
OFFSET

1,7

COMMENT

Sum(k=1,n,a(k)) appears to be asymptotic to C*n*Log(n) with C=0.4... - Benoit Cloitre (benoit7848c(AT)orange.fr), Aug 19 2002

Multiplicative with a(3) = 1, a(3^e) = 3, e >= 2, a((3k+1)^e) = 3, a((3k+2)^e) = 1. David W. Wilson (davidwwilson(AT)comcast.net) May 22, 2005.

LINKS

T. D. Noe, Table of n, a(n) for n=1..1000

S. R. Finch and Pascal Sebah, Squares and Cubes Modulo n (arXiv: math.NT/0604465).

FORMULA

Let b(n) be the number of primes dividing n which are congruent to 1 mod 3 (sequence A005088); then a(n) is 3^b(n) if n is not divisible by 9, and 3^(b(n) + 1) if n is divisible by 9.

Sequence is multiplicative. - David W. Wilson, Jan 06 2005.

EXAMPLE

a(7) = 3 because the three solutions to x^3 == 1 mod 7 are: x = 1,2,4

PROGRAM

(PARI) a(n)=sum(i=1, n, if((i^3-1)%n, 0, 1))

CROSSREFS

A005088, A060594.

Adjacent sequences: A060836 A060837 A060838 this_sequence A060840 A060841 A060842

Sequence in context: A051718 A016472 A095346 this_sequence A088204 A100375 A066975

KEYWORD

nonn,nice,easy,mult

AUTHOR

Ahmed Fares (ahmedfares(AT)my-deja.com), May 02 2001

EXTENSIONS

More terms from Larry Reeves (larryr(AT)acm.org), May 03 2001

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Last modified May 11 10:28 EDT 2008. Contains 139662 sequences.


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