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A069929 Number of k, 1<=k<=n, such that k^3+1 divides n^3+1. 0
1, 1, 2, 1, 3, 1, 2, 2, 2, 1, 3, 1, 2, 2, 2, 1, 4, 1, 3, 2, 2, 1, 3, 1, 2, 3, 3, 1, 3, 1, 3, 2, 2, 1, 3, 1, 2, 2, 2, 1, 4, 1, 2, 2, 2, 1, 5, 1, 3, 2, 2, 1, 3, 1, 3, 2, 2, 1, 5, 1, 3, 2, 2, 2, 3, 1, 2, 3, 4, 1, 3, 1, 2, 2, 4, 1, 3, 1, 2, 2, 2, 1, 5, 1, 2, 2, 3, 1, 4, 1, 2, 2, 2, 1, 3, 1, 2, 2, 2, 1, 4, 1, 4, 2, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..105.

FORMULA

Conjecture : (1/n)*sum(k=1, n, a(k)) = C*ln(ln(n))+o(ln(ln(n)) with 1<C<3/2

PROG

(PARI) for(n=1, 150, print1(sum(i=1, n, if((n^3+1)%(i^3+1), 0, 1)), ", "))

CROSSREFS

Cf. A066743.

Sequence in context: A206778 A101872 A174892 * A101312 A241273 A154263

Adjacent sequences:  A069926 A069927 A069928 * A069930 A069931 A069932

KEYWORD

easy,nonn

AUTHOR

Benoit Cloitre, May 05 2002

STATUS

approved

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Last modified November 22 08:48 EST 2014. Contains 249805 sequences.