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A346321
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Number of permutations of [n] having six cycles of the form (c1, c2, ..., c_m) where c1 = min_{i>=1} c_i and c_j = min_{i>=j} c_i or c_j = max_{i>=j} c_i.
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2
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1, 21, 322, 4284, 52941, 627627, 7264499, 82948008, 940359420, 10628025408, 120071145376, 1358324810752, 15403850755456, 175232115148032, 2000450203866368, 22922052379355136, 263639657993643008, 3043516686354636800, 35260990780587196416, 409914386080322027520
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OFFSET
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6,2
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LINKS
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Index entries for linear recurrences with constant coefficients, signature (112, -5880, 192416, -4402160, 74858880, -981976576, 10178341888, -84702207744, 571843371008, -3151736133632, 14222131077120, -52534235435008, 158334587600896, -386804516978688, 757761436024832, -1171275127980032, 1394246317768704, -1231344289972224, 758836566687744, -290924978503680, 52183852646400).
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MAPLE
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b:= proc(n) option remember; series(`if`(n=0, 1, add(b(n-j)
*binomial(n-1, j-1)*x*ceil(2^(j-2)), j=1..n)), x, 7)
end:
a:= n-> coeff(b(n), x, 6):
seq(a(n), n=6..29);
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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