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A238950 The number of arcs from even to odd level vertices in divisor lattice D(n). 3
0, 1, 1, 1, 1, 2, 1, 2, 1, 2, 1, 4, 1, 2, 2, 2, 1, 4, 1, 4, 2, 2, 1, 5, 1, 2, 2, 4, 1, 6, 1, 3, 2, 2, 2, 6, 1, 2, 2, 5, 1, 6, 1, 4, 4, 2, 1, 7, 1, 4, 2, 4, 1, 5, 2, 5, 2, 2, 1, 10, 1, 2, 4, 3, 2, 6, 1, 4, 2, 6, 1, 9, 1, 2, 4, 4, 2, 6, 1, 7, 2, 2, 1, 10, 2, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,6

LINKS

R. J. Mathar, Table of n, a(n) for n = 1..1000

S.-H. Cha, E. G. DuCasse, and L. V. Quintas, Graph Invariants Based on the Divides Relation and Ordered by Prime Signatures, arXiv:1405.5283 [math.NT], 2014 (see 11th line in Table 1).

FORMULA

a(n) = A062799(n)-A238951(n). - Eq. (2.37) [Cha] - R. J. Mathar, May 27 2017

MAPLE

read("transforms") :

omega := [seq(A001221(n), n=1..1000)] :

ones := [seq(1, n=1..1000)] :

a062799 := DIRICHLET(ones, omega) ;

for n from 1 do

    a238951 := floor(op(n, a062799)/2) ;

    a238950 := op(n, a062799)-floor(op(n, a062799)/2) ;

    printf("%d %d\n", n, a238950) ;

end do: # R. J. Mathar, May 28 2017

CROSSREFS

Cf. A038548.

Sequence in context: A214716 A116933 A194448 * A088433 A264440 A303386

Adjacent sequences:  A238947 A238948 A238949 * A238951 A238952 A238953

KEYWORD

nonn

AUTHOR

Sung-Hyuk Cha, Mar 07 2014

STATUS

approved

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Last modified March 30 21:56 EDT 2020. Contains 333132 sequences. (Running on oeis4.)