OFFSET
1,3
COMMENTS
The Heinz number of a partition (y_1,...,y_k) is prime(y_1)*...*prime(y_k). This gives a bijective correspondence between positive integers and integer partitions.
EXAMPLE
The 12th divisible pair is (2,6) so a(12) = 2.
MATHEMATICA
primeMS[n_]:=If[n==1, {}, Flatten[Cases[FactorInteger[n], {p_, k_}:>Table[PrimePi[p], {k}]]]];
Join@@Table[Cases[primeMS[n], {x_, y_}/; Divisible[y, x]:>x, {0}], {n, 1000}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, Nov 02 2022
STATUS
approved