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 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 (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 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 Cf. A056924, A062799, A238950. Sequence in context: A329747 A304455 A345354 * A071466 A155041 A334296 Adjacent sequences:  A238948 A238949 A238950 * A238952 A238953 A238954 KEYWORD nonn AUTHOR Sung-Hyuk Cha, Mar 07 2014 STATUS approved

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Last modified May 17 13:48 EDT 2022. Contains 353746 sequences. (Running on oeis4.)