A238960 -id:A238960 - cp's OEIS frontend

A238959 The number of arcs from even to odd level vertices in divisor lattice in graded colexicographic order.

0, 1, 1, 2, 2, 4, 6, 2, 5, 6, 10, 16, 3, 7, 9, 14, 17, 26, 40, 3, 8, 11, 12, 18, 23, 27, 36, 42, 64, 96, 4, 10, 14, 16, 22, 30, 32, 38, 46, 58, 68, 88, 102, 152, 224, 4, 11, 16, 19, 20, 26, 36, 41, 48, 52, 56, 74, 80, 93, 108, 112, 140, 162, 208, 240, 352, 512

Offset: 0

Sung-Hyuk Cha, Mar 07 2014

			Triangle T(n,k) begins:
  0;
  1;
  1, 2;
  2, 4,  6;
  2, 5,  6, 10, 16;
  3, 7,  9, 14, 17, 26, 40;
  3, 8, 11, 12, 18, 23, 27, 36, 42, 64, 96;
  ...

Andrew Howroyd, Table of n, a(n) for n = 0..2713 (rows 0..20)
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.

Cf. A238950 in graded colexicographic order.

Cf. A036035, A238953, A238960, A238972.

T(n,k) = A238950(A036035(n,k)).
From Andrew Howroyd, Apr 25 2020: (Start)
T(n,k) = ceiling(A238953(n,k)/2).
T(n,k) = A238953(n,k) - A238960(n,k). (End)

Offset changed and terms a(50) and beyond from Andrew Howroyd, Apr 25 2020

A238973 The number of arcs from odd to even level vertices in divisor lattice in canonical order.

Original entry on oeis.org

0, 0, 1, 2, 1, 3, 6, 2, 5, 6, 10, 16, 2, 6, 8, 14, 16, 26, 40, 3, 8, 11, 18, 12, 23, 36, 27, 42, 64, 96, 3, 9, 13, 22, 15, 29, 46, 32, 37, 58, 88, 67, 102, 152, 224, 4, 11, 16, 26, 19, 36, 56, 20, 41, 48, 74, 112, 52, 80, 93, 140, 208, 108, 162, 240, 352, 512

Offset: 0

Sung-Hyuk Cha, Mar 07 2014

			Triangle T(n,k) begins:
  0;
  0;
  1, 2;
  1, 3,  6;
  2, 5,  6, 10, 16;
  2, 6,  8, 14, 16, 26, 40;
  3, 8, 11, 18, 12, 23, 36, 27, 42, 64, 96;
  ...

Andrew Howroyd, Table of n, a(n) for n = 0..2713 (rows 0..20)
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.

Cf. A238960 in canonical order.

Cf. A063008, A238951, A238964, A238972.

From Andrew Howroyd, Mar 28 2020: (Start)
T(n,k) = A238951(A063008(n,k)).
T(n,k) = A238964(n,k) - A238972(n,k).
T(n,k) = floor(A238964(n,k)/2). (End)

Offset changed and terms a(50) and beyond from Andrew Howroyd, Mar 28 2020

cp's OEIS Frontend

A238959 The number of arcs from even to odd level vertices in divisor lattice in graded colexicographic order.

Views

Author

Keywords

Examples

Links

Crossrefs

Formula

Extensions