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A122977 Number of sublattices of the divisor lattice of divisors of n that include n. 5

%I

%S 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,

%T 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,

%U 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

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

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

%F a(A002110(n)) = A326878(n). - _Andrew Howroyd_, Apr 17 2020

%e 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}.

%Y Cf. A051839, A074986, A122978, A122979, A122980, A326878.

%K nonn,nice

%O 1,2

%A _Franklin T. Adams-Watters_, Sep 21 2006

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Last modified June 21 03:51 EDT 2021. Contains 345354 sequences. (Running on oeis4.)