login
A238951
The number of arcs from odd to even level vertices in divisor lattice D(n).
4
0, 0, 0, 1, 0, 2, 0, 1, 1, 2, 0, 3, 0, 2, 2, 2, 0, 3, 0, 3, 2, 2, 0, 5, 1, 2, 1, 3, 0, 6, 0, 2, 2, 2, 2, 6, 0, 2, 2, 5, 0, 6, 0, 3, 3, 2, 0, 6, 1, 3, 2, 3, 0, 5, 2, 5, 2, 2, 0, 10, 0, 2, 3, 3, 2, 6, 0, 3, 2, 6, 0, 8, 0, 2, 3, 3, 2, 6, 0, 6, 2, 2, 0, 10, 2, 2
OFFSET
1,6
LINKS
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 12th line in Table 1).
FORMULA
a(n) = A062799(n) - A238950(n) = floor(A062799(n)/2). [Cha eqs. (2.34), (2.37)]
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) ;
printf("%d %d\n", n, a238951) ;
end do: # R. J. Mathar, May 28 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Sung-Hyuk Cha, Mar 07 2014
STATUS
approved