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.

A110148 Number of perfect squared rectangles of order n up to symmetries of the rectangle and of its subrectangles if any.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 2, 10, 38, 127, 408, 1375, 4783, 16645, 58059, 203808, 722575
Offset: 1

Views

Author

Tanya Khovanova, Feb 18 2007

Keywords

Comments

A squared rectangle (which may be a square) is a rectangle dissected into a finite number, two or more, of squares. If no two of these squares have the same size the squared rectangle is perfect. The order of a squared rectangle is the number of constituent squares. [Geoffrey H. Morley, Oct 12 2012]

Crossrefs

Cf. A217154 (counts symmetries of any subrectangles as distinct).

Formula

a(n) = A002839(n) + A217152(n) + A217374(n). - Geoffrey H. Morley, Oct 12 2012
a(n) = a(n-1) + A002839(n) + A002839(n-1) + A217152(n) + A217152(n-1). - Geoffrey H. Morley, Oct 12 2012

Extensions

Definition corrected and a(14)-a(19) added by Geoffrey H. Morley, Oct 12 2012

A217375 Number of trivially compound perfect squared rectangles of order n up to symmetries of the rectangle.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 0, 8, 40, 168, 604, 2076, 7320, 26132, 93352, 333992, 1199716, 4329180
Offset: 1

Views

Author

Geoffrey H. Morley, Oct 02 2012

Keywords

Comments

A squared rectangle is a rectangle dissected into a finite number, two or more, of squares. If no two of these squares have the same size the squared rectangle is perfect. The order of a squared rectangle is the number of constituent squares.
A squared rectangle is simple if it does not contain a smaller squared rectangle, compound if it does, and trivially compound if a constituent square has the same side length as a side of the squared rectangle under consideration.

Crossrefs

Cf. A217374 (counts symmetries of squared subrectangles as equivalent).
Cf. A217154.

Formula

a(n) >= 2*a(n-1) + 4*A002839(n-1) + 4*A217153(n-1), with equality for n<19.

Extensions

a(20) corrected by Geoffrey H. Morley, Oct 12 2012
Showing 1-2 of 2 results.