OFFSET
1,2
COMMENTS
The Heinz number of an integer partition or multiset {y_1,...,y_k} is prime(y_1)*...*prime(y_k).
FORMULA
EXAMPLE
The sequence of terms together with their prime indices begins:
1: ()
2: (1)
3: (2)
6: (2,1)
7: (4)
20: (3,1,1)
13: (6)
42: (4,2,1)
39: (6,2)
110: (5,3,1)
29: (10)
312: (6,2,1,1,1)
37: (12)
374: (7,5,1)
261: (10,2,2)
798: (8,4,2,1)
53: (16)
2300: (9,3,3,1,1)
61: (18)
3828: (10,5,2,1,1)
For example, the divisors of 6 are {1,2,3,6}, with differences {1,1,3}, with Heinz number 20, so a(6) = 20.
MATHEMATICA
Table[Times@@Prime/@Differences[Divisors[n]], {n, 100}]
CROSSREFS
The sorted version is A328024.
KEYWORD
nonn
AUTHOR
Gus Wiseman, Oct 02 2019
STATUS
approved