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A317288
Number of permutations of [n] with exactly eight increasing runs of even length.
2
19391512145, 1367267690953, 57188581537971, 2006576231088264, 65823539327956911, 2066450841399035025, 63056350327027739274, 1900463594609383889937, 57088794679037177345346, 1717519261928956311195227, 51966007918370324842446184, 1586467824560962829102119877
OFFSET
16,1
LINKS
MAPLE
b:= proc(u, o, t) option remember; series(`if`(u+o=0, x^t,
add(b(u+j-1, o-j, irem(t+1, 2)), j=1..o)+
add(b(u-j, o+j-1, 0)*x^t, j=1..u)), x, 9)
end:
a:= n-> coeff(b(n, 0$2), x, 8):
seq(a(n), n=16..30);
CROSSREFS
Column k=8 of A097592.
Sequence in context: A273186 A185932 A262533 * A234397 A234194 A118466
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Jul 25 2018
STATUS
approved