A055622 Minimum solution for tri-color tower of Hanoi, restricted so like colors can't be together.

1, 3, 7, 19, 43, 99, 235, 535, 1239, 2879, 6619, 15323, 35451, 81823, 189263, 437543, 1011059, 2337731, 5403987, 12491223, 28877687, 66755519, 154315883, 356738411, 824668747, 1906384015, 4407016991, 10187707927, 23550975203

Offset: 1

Author

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

Keywords

• nonn

Links

• William H. Paulsen, Tri-color Tower of Hanoi

Formula

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).

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]

Extensions

G.f. proposed by Maksym Voznyy checked and corrected by R. J. Mathar, Sep 16 2009

Additional comments from Robert G. Wilson v, Nov 02 2001