A055622 - OEIS

%I #9 Jun 06 2018 07:17:19

%S 1,3,7,19,43,99,235,535,1239,2879,6619,15323,35451,81823,189263,

%T 437543,1011059,2337731,5403987,12491223,28877687,66755519,154315883,

%U 356738411,824668747,1906384015,4407016991,10187707927,23550975203

%N Minimum solution for tri-color tower of Hanoi, restricted so like colors can't be together.

%H William H. Paulsen, <a href="http://www.csm.astate.edu/~wpaulsen/tower/hanoi.htm">Tri-color Tower of Hanoi</a>

%F a(n) = a(n-1) + 2 a(n-2) + 7 a(n-3) - 5 a(n-4) - 8 a(n-5) - 14 a(n-6) + 2 a(n-7) + 4 a(n-8) + 4 a(n-9) + 8 a(n-10).

%F G.f.: x*(1+2*x+2*x^2-x^3-6*x^4-8*x^5-10*x^6-8*x^7-4*x^8)/ ((1-x) * (2*x^5+3*x^3-1) * (4*x^4+6*x^3+2*x^2-1)). [From Maksym Voznyy (voznyy(AT)mail.ru), Jul 27 2009]

%K nonn

%O 1,2

%A William H. Paulsen (wpaulsen(AT)csm.astate.edu), Jun 04 2000

%E G.f. proposed by Maksym Voznyy checked and corrected by _R. J. Mathar_, Sep 16 2009

%E Additional comments from _Robert G. Wilson v_, Nov 02 2001