A144855 - OEIS

The OEIS is supported by the many generous donors to the OEIS Foundation.

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give

A144855

Number of paths from (1,1) to (n,n) in an n X n grid using only the steps +(1,0), -(1,0), +(0,1) and -(0,1) which do not self-intersect and which avoid any point (p,q) satisfying "(p-1)*n + q is prime".

1, 0, 0, 0, 0, 0, 0, 254, 0, 0, 0, 0, 0

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,8

LINKS

Table of n, a(n) for n=1..13.

EXAMPLE

One of the 254 prime avoiding paths for the n=8 case is 1,9,10,18,26,27,28,20,21,22,14,15,16,24,32,40,39,38,46,54,55,56,64

CROSSREFS

Sequence in context: A243666 A243687 A263380 * A110827 A062664 A258696

Adjacent sequences: A144852 A144853 A144854 * A144856 A144857 A144858

KEYWORD

hard,more,nonn

AUTHOR

Joseph E. Cooper III (easonrevant(AT)gmail.com), Sep 22 2008

STATUS

approved