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A317283
Number of permutations of [n] with exactly three increasing runs of even length.
2
61, 906, 8965, 94398, 1088575, 12625694, 150890533, 1914036434, 25485825638, 353702731940, 5141233861254, 78259458749608, 1243051438276365, 20579839942072222, 354951501710697119, 6367683567830126402, 118640486378324764141, 2293339890430027143606
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OFFSET
6,1
LINKS
Alois P. Heinz,
Table of n, a(n) for n = 6..472
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, 4)
end:
a:= n-> coeff(b(n, 0$2), x, 3):
seq(a(n), n=6..30);
CROSSREFS
Column k=3 of
A097592
.
Sequence in context:
A093473
A000506
A008358
*
A264306
A138790
A057534
Adjacent sequences:
A317280
A317281
A317282
*
A317284
A317285
A317286
KEYWORD
nonn
AUTHOR
Alois P. Heinz
, Jul 25 2018
STATUS
approved
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Last modified August 20 09:14 EDT 2024. Contains 375325 sequences. (Running on oeis4.)