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%I M2800 #17 Sep 26 2017 02:51:22
%S 1,3,9,25,70,194,537,1485,4104,11338,31318,86498,238885,659713,
%T 1821843,5031071,13893316,38366206,105947374,292570493,807923428,
%U 2231050832,6160961041,17013250192,46981405457,129737238488,358264064448,989331456469
%N Number of irreducible positions of size n in Montreal solitaire.
%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H C. Cannings, J. Haigh, <a href="https://doi.org/10.1016/0097-3165(92)90037-U">Montreal solitaire</a>, J. Combin. Theory Ser. A 60 (1992), no. 1, 50-66.
%F a(n) = d(n, 2) where d(n, k) = 0 if n < k*(k+1)/2, d(n, k) = 1 if n = k*(k+1)/2, and d(n, k) = d(n, k+1) + Sum_{r=1..k} binomial(k + 1, r) * d(n - k*(k+1)/2 + r*(r-1)/2, r) if n > k*(k+1)/2 [From Cannings and Haigh]. - _Sean A. Irvine_, Sep 25 2017
%Y Cf. A007048, A007049, A007050, A007075, A007076.
%K nonn
%O 3,2
%A _N. J. A. Sloane_, _Mira Bernstein_
%E More terms from _Sean A. Irvine_, Sep 25 2017
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