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A321066 Number of ordered pairs (p,q) of permutations of [n] with equal up-down signatures and p(1)=q(1)=10. 2
1035227008, 48904686848, 2945846638464, 218405906177792, 19438574276705792, 2038137238577944576, 248048061418810109952, 34621419911316556017664, 5486719044572824902107136, 978934483626207520876986368, 195206678980725195413273903104 (list; graph; refs; listen; history; text; internal format)
OFFSET
10,1
LINKS
MAPLE
b:= proc(u, o, h) option remember; `if`(u+o=0, 1,
add(add(b(u-j, o+j-1, h+i-1), i=1..u+o-h), j=1..u)+
add(add(b(u+j-1, o-j, h-i), i=1..h), j=1..o))
end:
a:= n-> (k-> b(k-1, n-k, n-k))(10):
seq(a(n), n=10..20);
CROSSREFS
Column k=10 of A262372.
Sequence in context: A268312 A035124 A197952 * A222531 A167476 A051019
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Oct 26 2018
STATUS
approved

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Last modified February 24 10:53 EST 2024. Contains 370295 sequences. (Running on oeis4.)