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.

A141226 Numbers n such that the central point of the square n x n lattice sees the maximal number of points.

Original entry on oeis.org

1, 3, 11, 23, 27, 35, 39, 47, 59, 95, 147, 167, 179, 207, 219, 227, 279, 347, 363, 399, 543, 567, 587, 627, 767, 779, 935
Offset: 1

Views

Author

T. D. Noe, Jun 15 2008, Jun 17 2008

Keywords

Comments

These n are the numbers for which A141225(n) is odd. Note that n must be odd. When A141225(n)=1, the central point is the only point seeing the maximal number of points. Except for 1, these numbers are 3 or 11 (mod 12).
These numbers also seem to produce cubic n x n x n lattices in which the central point has maximal visibility; see A141228. Note that for n>3, n-1 is twice a prime in A141246.

A141250 Prime powers related to minimal visibility in the square n X n lattice.

Original entry on oeis.org

11, 17, 23, 37, 41, 97, 101, 121, 137, 157, 191, 211, 223, 227, 331, 347, 431, 443, 457
Offset: 1

Views

Author

T. D. Noe, Jun 17 2008

Keywords

Comments

So far 121 is the only composite here. The numbers in A141249 greater than 1 are 2*a(n)-1.

Crossrefs

Cf. A141246.
Showing 1-2 of 2 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement.