login
A331381
Number of integer partitions of n whose sum of primes of parts is divisible by their product of parts.
16
1, 1, 1, 1, 1, 3, 1, 5, 2, 6, 6, 5, 5, 7, 4, 7, 7, 7, 10, 8, 9, 6, 10, 9, 9, 15, 7, 12, 10, 14, 10, 10, 8, 8, 15, 10, 7, 16, 13, 9, 10, 14, 12, 10, 8, 14, 11, 13, 11, 16, 15, 14, 15, 15, 10, 14, 18, 11, 12, 13, 13, 18, 21, 15, 16, 19, 16, 15, 8, 17, 17
OFFSET
0,6
EXAMPLE
The a(n) partitions for n = 1, 5, 7, 8, 9, 13, 14:
1 221 43 311111 63 7411 65111
311 511 11111111 441 721111 322211111
11111 3211 711 43111111 311111111111
22111 42111 421111111 11111111111111
1111111 2211111 3211111111
111111111 22111111111
1111111111111
MATHEMATICA
Table[Length[Select[IntegerPartitions[n], Divisible[Plus@@Prime/@#, Times@@#]&]], {n, 0, 30}]
CROSSREFS
The Heinz numbers of these partitions are given by A331382.
Numbers divisible by the sum of their prime factors are A036844.
Partitions whose product is divisible by their sum are A057568.
Numbers divisible by the sum of their prime indices are A324851.
Product of prime indices is divisible by sum of prime indices: A326149.
Partitions whose Heinz number is divisible by their sum are A330950.
Sum of prime factors is divisible by sum of prime indices: A331380
Partitions whose product is equal to their sum of primes are A331383.
Product of prime indices equals sum of prime factors: A331384.
Sequence in context: A225080 A276505 A201901 * A174239 A066249 A065168
KEYWORD
nonn
AUTHOR
Gus Wiseman, Jan 16 2020
STATUS
approved