OFFSET
0,4
COMMENTS
Appears to approximately double (for n > 1) for each successive n. - Chai Wah Wu, Aug 26 2017
LINKS
Chai Wah Wu, Table of n, a(n) for n = 0..120
EXAMPLE
5 divides 5^3,
5 + 4 divides 5^3 + 4^3,
5 + 4 + 3 divides 5^3 + 4^3 + 3^3,
5 + 4 + 3 + 2 divides 5^3 + 4^3 + 3^3 + 2^3,
5 + 4 + 3 + 2 + 1 divides 5^3 + 4^3 + 3^3 + 2^3 + 1^3.
So [5, 4, 3, 2, 1] satisfies all the conditions.
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a(1) = 1: [[1]];
a(2) = 1: [[2, 1]];
a(3) = 2: [[2, 3, 1], [3, 2, 1]];
a(4) = 6: [[2, 3, 4, 1], [2, 4, 3, 1], [3, 2, 4, 1], [3, 4, 2, 1], [4, 2, 3, 1], [4, 3, 2, 1]];
a(5) = 18: [[2, 3, 4, 5, 1], [2, 3, 5, 4, 1], [2, 4, 3, 5, 1], [2, 5, 3, 4, 1], [3, 2, 4, 5, 1], [3, 2, 5, 4, 1], [3, 4, 2, 5, 1], [3, 4, 5, 2, 1], [3, 5, 2, 4, 1], [3, 5, 4, 2, 1], [4, 2, 3, 5, 1], [4, 3, 2, 5, 1], [4, 3, 5, 2, 1], [4, 5, 3, 2, 1], [5, 2, 3, 4, 1], [5, 3, 2, 4, 1], [5, 3, 4, 2, 1], [5, 4, 3, 2, 1]].
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Aug 25 2017
EXTENSIONS
a(0), a(14)-a(33) from Alois P. Heinz, Aug 25 2017
STATUS
approved