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 A007046 Number of irreducible positions of size n in Montreal solitaire. (Formerly M2800) 5
 1, 3, 9, 25, 70, 194, 537, 1485, 4104, 11338, 31318, 86498, 238885, 659713, 1821843, 5031071, 13893316, 38366206, 105947374, 292570493, 807923428, 2231050832, 6160961041, 17013250192, 46981405457, 129737238488, 358264064448, 989331456469 (list; graph; refs; listen; history; text; internal format)
 OFFSET 3,2 REFERENCES N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). LINKS C. Cannings, J. Haigh, Montreal solitaire, J. Combin. Theory Ser. A 60 (1992), no. 1, 50-66. FORMULA 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 CROSSREFS Cf. A007048, A007049, A007050, A007075, A007076. Sequence in context: A297590 A244934 A291594 * A211286 A211285 A333498 Adjacent sequences:  A007043 A007044 A007045 * A007047 A007048 A007049 KEYWORD nonn AUTHOR EXTENSIONS More terms from Sean A. Irvine, Sep 25 2017 STATUS approved

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Last modified December 5 16:13 EST 2021. Contains 349557 sequences. (Running on oeis4.)