[go: up one dir, main page]

login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A322530
Number of integer partitions of n with no 1's whose product of parts is a squarefree number.
7
1, 0, 1, 1, 0, 2, 1, 2, 1, 1, 3, 2, 2, 4, 3, 3, 3, 6, 5, 5, 5, 6, 8, 8, 9, 8, 11, 8, 12, 13, 16, 14, 13, 16, 21, 18, 21, 25, 22, 24, 27, 35, 33, 33, 32, 37, 42, 47, 48, 48, 52, 51, 59, 70, 68, 65, 69, 80, 87, 90, 103, 100, 96, 103, 123, 128, 135, 136, 132, 153
OFFSET
0,6
COMMENTS
Such a partition must be strict and its parts must also be squarefree.
EXAMPLE
The a(26) = 11 integer partitions:
(26),
(15,11), (19,7), (21,5), (23,3),
(13,7,6), (13,10,3), (13,11,2), (17,7,2), (19,5,2),
(11,7,5,3).
MATHEMATICA
Table[Length[Select[IntegerPartitions[n], !MemberQ[#, 1]&&SquareFreeQ[Times@@#]&]], {n, 30}]
KEYWORD
nonn
AUTHOR
Gus Wiseman, Dec 14 2018
STATUS
approved