A158074 - OEIS

%I #16 Apr 18 2018 08:36:25

%S 0,0,0,0,32,352,3072,30848,295456,2896832,28120096,273895232,

%T 2664515712,25931157504,252338724352,2455552258304,23895692937216,

%U 232533011307776,2262837745837568,22020130538878208,214282979451801088,2085233793265765376,20291876152214982656

%N Number of (directed) Hamiltonian cycles on a 3 X (2n) knight's tour graph.

%H Seiichi Manyama, <a href="/A158074/b158074.txt">Table of n, a(n) for n = 1..1000</a>

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/KnightsTour.html">Knight's Tour</a>

%F a(n) = 2*A070030(n).

%F a(n) = 6*a(n-1) + 64*a(n-2) - 200*a(n-3) - 1000*a(n-4) + 3016*a(n-5) + 3488*a(n-6) - 24256*a(n-7) + 23776*a(n-8) + 104168*a(n-9) - 203408*a(n-10) - 184704*a(n-11) + 443392*a(n-12) + 14336*a(n-13) - 151296*a(n-14) + 145920*a(n-15) - 263424*a(n-16) + 317440*a(n-17) + 36864*a(n-18) - 966656*a(n-19) + 573440*a(n-20) + 131072*a(n-21), for n>=23. (See A070030) - _Seiichi Manyama_, Dec 16 2016

%Y Cf. A070030 for details and references.

%K nonn

%O 1,5

%A _Eric W. Weisstein_, Mar 13 2009

%E Extended by _Eric W. Weisstein_, Mar 18 2009