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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

%I

%S 1,0,0,0,0,0,0,254,0,0,0,0,0

%N 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".

%e 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

%K hard,more,nonn

%O 1,8

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

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Last modified January 23 11:38 EST 2021. Contains 340385 sequences. (Running on oeis4.)