|
|
A325337
|
|
Numbers whose prime exponents are distinct and cover an initial interval of positive integers.
|
|
18
|
|
|
1, 2, 3, 5, 7, 11, 12, 13, 17, 18, 19, 20, 23, 28, 29, 31, 37, 41, 43, 44, 45, 47, 50, 52, 53, 59, 61, 63, 67, 68, 71, 73, 75, 76, 79, 83, 89, 92, 97, 98, 99, 101, 103, 107, 109, 113, 116, 117, 124, 127, 131, 137, 139, 147, 148, 149, 151, 153, 157, 163, 164
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
COMMENTS
|
The Heinz number of an integer partition (y_1,...,y_k) is prime(y_1)*...*prime(y_k), so these are Heinz numbers of integer partitions with distinct multiplicities covering an initial interval of positive integers. The enumeration of these partitions by sum is given by A320348.
|
|
LINKS
|
|
|
EXAMPLE
|
The sequence of terms together with their prime indices begins:
1: {}
2: {1}
3: {2}
5: {3}
7: {4}
11: {5}
12: {1,1,2}
13: {6}
17: {7}
18: {1,2,2}
19: {8}
20: {1,1,3}
23: {9}
28: {1,1,4}
29: {10}
31: {11}
37: {12}
41: {13}
43: {14}
44: {1,1,5}
|
|
MATHEMATICA
|
normQ[m_]:=Or[m=={}, Union[m]==Range[Max[m]]];
Select[Range[100], UnsameQ@@Last/@FactorInteger[#]&&normQ[Last/@FactorInteger[#]]&]
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|