A335152 Number of vertices in polytope representing the number n.

1, 2, 3, 3, 4, 5, 6, 6, 5, 6, 7, 8, 9, 10, 11, 10, 11, 12, 13, 13, 14, 15, 16, 17, 15, 16, 15, 15, 16, 17, 18, 17, 18, 19, 20, 20, 21, 22, 23, 24, 25, 26, 27, 27, 28, 29, 30, 30, 26, 26, 27, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 36, 37, 38, 39, 39, 40, 41, 42, 42, 43, 44, 44, 44, 45, 46, 47, 48, 45, 46, 47, 48, 49, 50, 51, 51, 52, 53, 54, 54, 55, 56, 57, 58, 59, 58, 57, 55, 56, 57, 58, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 69, 68, 69, 70, 71, 66, 67, 68, 68, 66, 67, 68, 65, 66, 67, 68, 69, 70, 71, 72

Offset

1,2

Comments

More than the usual number of terms are shown here in order to distinguish this sequence from A064047. The two sequences first differ at n=128.

Comments from Ya-Ping Lu, May 25 2020 (Start):

Concerning the sequences A064047 and the number of vertices of the polytope representing n (the present sequence). These two sequences are similar but not exactly the same.

As you can see from the pdf file attached, for n<=127, A064047 is the same as N_vert. For n > =128, A064047 is always greater than or equal to N_vert. This is due to the fact that in some cases not all the non-vertex numbers on the polytope can be written as the geometric mean of two integers on the polytope. See also A334810 and A334897.

The cases where A064047 is greater than N_vert are highlighted in yellow in the attached file. (End)

Links

Table of n, a(n) for n=1..135.

Ya-Ping Lu and Shu-Fang Deng, Properties of Polytopes Representing Natural Numbers, arXiv:2003.08968 [math.GM], 2020.

Ya-Ping Lu, Table comparing A064047 (column 2) and a(n) (column 3). [Yellow lines show where the values are different.]

Crossrefs

Cf. A064047, A333524, A334810, A334897.

Sequence in context: A320033 A333527 A064047 * A111899 A074753 A013928

Adjacent sequences: A335149 A335150 A335151 * A335153 A335154 A335155

Keyword

nonn

Author

N. J. A. Sloane, May 25 2020, based on correspondence with Ya-Ping Lu.

Status

approved