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A332955
a(0) = 1 and a(n) = A309807(n) - A309807(n-1) for n > 0.
1
1, 0, 0, 1, 1, 3, 3, 10, 11, 30, 48, 114, 166, 486, 727, 1643, 3193, 7619, 12489, 30781, 52007, 123418, 248386, 520902, 909701, 2349536, 4417148, 9055904, 18451951, 41215779, 77052793, 186393151, 350380117, 769533521
OFFSET
0,6
COMMENTS
See A309807.
PROG
(Ruby)
def A(n)
(1..n).to_a.permutation.select{|i| (1..n - 1).all?{|j| i[j - 1] * (j + 1) > i[j] * j}}.size
end
def A332955(n)
a = (0..n).map{|i| A(i)}
[1] + (1..n).map{|i| a[i] - a[i - 1]}
end
p A332955(10)
CROSSREFS
Cf. A309807.
Sequence in context: A321397 A128015 A233256 * A355089 A218953 A081809
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Mar 04 2020
EXTENSIONS
a(23)-a(25) from Giovanni Resta, Mar 04 2020
a(26)-a(33) from Bert Dobbelaere, Mar 15 2020
STATUS
approved