A238950 The number of arcs from even to odd level vertices in divisor lattice D(n).

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

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: A116933 A354060 A194448 * A088433 A335434 A348379

Adjacent sequences: A238947 A238948 A238949 * A238951 A238952 A238953

Keyword

nonn

Author

Sung-Hyuk Cha, Mar 07 2014

Status

approved