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%I #2 May 10 2013 12:45:52
%S 0,0,4,12,44,116,356,948,2772,7396,20972,56108,156236,418228,1151556,
%T 3081180,8421052,22514652,61207972,163518308,442769316,1181982628,
%U 3190663628,8511628124,22920057932,61104234356,164212633412
%N Number of n-step walks on square lattice, self-avoiding until the last step.
%C A001411(n)=4^n-(a(n)+4*(a(n-1)+4*(a(n-2)+...)))
%F a(n) = 4*A001411(n-1)-A001411(n), n>0. [From _Vladeta Jovovic_, Nov 02 2009]
%Y See references given for A001411.
%K nonn
%O 0,3
%A Vadim Sheikhman (vvsshh(AT)gmail.com), Nov 02 2009
%E More terms from _Vladeta Jovovic_, Nov 02 2009