A346321 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.

1, 21, 322, 4284, 52941, 627627, 7264499, 82948008, 940359420, 10628025408, 120071145376, 1358324810752, 15403850755456, 175232115148032, 2000450203866368, 22922052379355136, 263639657993643008, 3043516686354636800, 35260990780587196416, 409914386080322027520

Offset: 6

Author

Alois P. Heinz, Jul 13 2021

Keywords

• nonn
• easy

Links

• Alois P. Heinz, Table of n, a(n) for n = 6..932
• 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).

Crossrefs

Column k=6 of A344855.

Programs

Maple

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);