

A122977


Number of sublattices of the divisor lattice of divisors of n that include n.


5



1, 2, 2, 4, 2, 7, 2, 8, 4, 7, 2, 21, 2, 7, 7, 16, 2, 21, 2, 21, 7, 7, 2, 58, 4, 7, 8, 21, 2, 45, 2, 32, 7, 7, 7, 84, 2, 7, 7, 58, 2, 45, 2, 21, 21, 7, 2, 152, 4, 21, 7, 21, 2, 58, 7, 58, 7, 7, 2, 200, 2, 7, 21, 64, 7, 45, 2, 21, 7, 45, 2, 293, 2, 7, 21, 21, 7, 45, 2, 152, 16, 7, 2, 200, 7, 7
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OFFSET

1,2


COMMENTS

A divisor lattice is closed under GCD and LCM. First differences of A074986. Depends only on the prime signature of n.


LINKS

Table of n, a(n) for n=1..86.


FORMULA

a(A002110(n)) = A326878(n).  Andrew Howroyd, Apr 17 2020


EXAMPLE

The a(6) = 7 sublattices of {1,2,3,6} that include 6 are: {6}, {1,6}, {2,6}, {3,6}, {1,2,6}, {1,3,6}, {1,2,3,6}.


CROSSREFS

Cf. A051839, A074986, A122978, A122979, A122980, A326878.
Sequence in context: A331121 A057767 A207329 * A275870 A321721 A003980
Adjacent sequences: A122974 A122975 A122976 * A122978 A122979 A122980


KEYWORD

nonn,nice


AUTHOR

Franklin T. AdamsWatters, Sep 21 2006


STATUS

approved



