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A007780 Losing initial configurations in 2-hole Tchuka Ruma. 2

%I

%S 1,2,3,6,9,11,18,20,27,30,54,81,162,168,243,486,729,1458,2187,4374,

%T 6561,13122,19683,39366,59049,118098,177147,354294,531441,1062882,

%U 1594323,3188646,4782969,9565938,14348907,28697814,43046721,86093442

%N Losing initial configurations in 2-hole Tchuka Ruma.

%C The 2-hole Tchuka Ruma game cannot be won for the initial seeds 3^i (i>=1) or 2*3^i (i>=0). Though a sufficient condition, this is not necessary, as can be seen from the terms a(6)=11, a(8)=20, a(10)=30 and a(14)=168. - Pab Ter (pabrlos2(AT)yahoo.com), Nov 08 2005

%C If any further sporadic term exists, then it exceeds 6973568802. - _Sean A. Irvine_, Jan 25 2018

%H Sean A. Irvine, <a href="/A007780/b007780.txt">Table of n, a(n) for n = 1..46</a>

%H Paul J. Campbell, and Darrah P. Chavey, <a href="https://www.beloit.edu/computerscience/assets/tchuka.pdf">Tchuka Ruma Solitaire</a>, The UMAP Journal 16(4) (1995), 343-365.

%F Conjectures from _Colin Barker_, Jan 25 2018: (Start)

%F G.f.: x*(1 + 2*x - 7*x^5 - 9*x^6 - 13*x^7 - 27*x^8 - 30*x^9 - 27*x^10 - 9*x^11 - 75*x^13 - 243*x^14 - 18*x^15) / (1 - 3*x^2).

%F a(n) = 3*a(n-2) for n>2.

%F (End)

%K nonn

%O 1,2

%A _Darrah Chavey_

%E More terms from Pab Ter (pabrlos2(AT)yahoo.com), Nov 08 2005

%E More terms from _Sean A. Irvine_, Jan 25 2018

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Last modified October 26 14:28 EDT 2021. Contains 348267 sequences. (Running on oeis4.)