A245665 Number of permutations of length n with longest increasing subsequence of length 9.

1, 81, 3961, 153341, 5213287, 164060352, 4927007100, 143938455225, 4142847526101, 118504614869214, 3389618010035458, 97376389179852540, 2818543211543628620, 82388635477750176388, 2436180769576352799396, 72958306889459609898731, 2214789502139053994814716

Offset

9,2

Links

Alois P. Heinz, Table of n, a(n) for n = 9..60

Maple

h:= proc(l) local n; n:= nops(l); add(i, i=l)! /mul(mul(1+l[i]-j
    +add(`if`(l[k]>=j, 1, 0), k=i+1..n), j=1..l[i]), i=1..n) end:
g:= (n, i, l)-> `if`(n=0 or i=1, h([l[], 1$n])^2, `if`(i<1, 0,
                add(g(n-i*j, i-1, [l[], i$j]), j=0..n/i))):
a:= n-> g(n-9, min(n-9, 9), [9]):
seq(a(n), n=9..30);

Crossrefs

Column k=9 of A047874.

Sequence in context: A223501 A053108 A237100 * A016888 A205238 A006312

Adjacent sequences: A245662 A245663 A245664 * A245666 A245667 A245668

Keyword

nonn

Author

Alois P. Heinz, Jul 28 2014

Status

approved