login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo

Please make a donation to keep the OEIS running. We are now in our 56th year. In the past year we added 10000 new sequences and reached almost 9000 citations (which often say "discovered thanks to the OEIS").
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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". 0
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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified November 25 11:32 EST 2020. Contains 338623 sequences. (Running on oeis4.)