cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-2 of 2 results.

A381243 Number of hyperplanes defined by the nonzero differences of two permutations of order n.

Original entry on oeis.org

0, 0, 1, 6, 85, 1370, 30481, 778610, 24409645, 881325366, 36635553601, 1713454403210, 89415912126223, 5143372266050837, 323667807885619744, 22112062644980805684
Offset: 0

Views

Author

Max Alekseyev, Feb 17 2025

Keywords

Comments

Each of A175176(n) - 1 nonzero differences between two permutations (viewed as vectors) defines a hyperplane in the n-dimensional space. a(n) gives the number of pairwise distinct hyperplanes among them.

Crossrefs

A384035 Number of vector differences between two permutations of order n, up to multiplication by positive rational numbers and permutations of the components.

Original entry on oeis.org

1, 1, 2, 4, 13, 49, 228, 1034, 5133, 25710, 133872, 708976, 3846150, 21170077, 118429072, 670537495
Offset: 0

Views

Author

Max Alekseyev, May 17 2025

Keywords

Examples

			For n = 3, there are A019589(3) = 5 difference vectors up to permutation of components: (-2, 0, 2), (-2, 1, 1), (-1, -1, 2), (-1, 0, 1), and (0, 0, 0). However, (-2, 0, 2) and (-1, 0, 1) are the same up to a factor 2. Hence, a(3) = 4.
		

Crossrefs

Showing 1-2 of 2 results.