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A217676
Number of permutations in S_n containing an increasing subsequence of length 9.
3
1, 82, 4062, 159404, 5497718, 175652924, 5360393100, 159281625000, 4667810722500, 136102249609224, 3973117419487320, 116645785269445696, 3455520662446396976, 103544836992023092832, 3144187412886704149472, 96883566754646092037696, 3032518386648514382974097
OFFSET
9,2
LINKS
FORMULA
a(n) = A214152(n,9) = A000142(n)-A072132(n) = A000142(n)-A214015(n,8).
EXAMPLE
a(9) = 1: 123456789.
MAPLE
b:= proc(n) option remember; `if`(n<4, n!,
(-147456*(n+4)*(n-1)^2*(n-2)^2*(n-3)^2*b(n-4)
+128*(33876+30709*n+6687*n^2+410*n^3)*(n-1)^2*(n-2)^2*b(n-3)
-4*(1092*n^5+37140*n^4+455667*n^3+2387171*n^2+4649270*n+1206000)*
(n-1)^2*b(n-2) +(-17075520+(22488312+(29223280+(10509820+(1764252+
(154164+(6804+120*n)*n)*n)*n)*n)*n)*n)*b(n-1))/
((n+16)*(n+7)^2*(n+15)^2*(n+12)^2))
end:
a:= n-> n! -b(n):
seq(a(n), n=9..30);
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Oct 10 2012
STATUS
approved