%I A051436
%S A051436 1,2,5,12,39,111,350,1044,3201,9627,29150,87672,264069,793431,2384450,
%T A051436 7159164,21494001,64507827,193589270,580878432,1742897949,5229157551,
%U A051436 15688522250
%N A051436 Undirected walks of length n+1 on tetrahedron, visiting n+2 vertices, 
               with n "corners", as in A001998, but allowing only rigid motions 
               in 3-space (|G| = 12). Walks are not self-avoiding.
%F A051436 n=2m: (3^n+3^m)/2 -2^(n-1)+2^(m-1); n=2m+1: (3^n+3^m)/2 - 2^(n-1) +1
%e A051436 For n=2 there are three walks that stay in one face and two that visit 
               two faces.
%Y A051436 Cf. A001998, A001444.
%Y A051436 Sequence in context: A036782 A050237 A050258 this_sequence A054581 A140440 
               A005664
%Y A051436 Adjacent sequences: A051433 A051434 A051435 this_sequence A051437 A051438 
               A051439
%K A051436 nonn,nice,easy
%O A051436 0,2
%A A051436 Colin Mallows colinm(AT)research.avayalabs.com
%E A051436 Corrected by T. D. Noe (noe(AT)sspectra.com), Nov 09 2006