OFFSET
1,3
COMMENTS
The Heinz number of an integer partition (y_1, ..., y_k) is prime(y_1) * ... * prime(y_k).
Also the number of size-preserving permutations of multiset partitions of a multiset (such as row n of A305936) whose multiplicities are the prime indices of n.
LINKS
EXAMPLE
The sum of coefficients of h(211) = m(4) + 4m(22) + 3m(31) + 7m(211) + 12m(1111) is a(12) = 27.
The a(3) = 2 through a(9) = 16 size-preserving permutations of multiset partitions:
{11} {12} {111} {112} {1111} {123} {1122}
{1}{1} {1}{2} {1}{11} {1}{12} {1}{111} {1}{23} {1}{122}
{2}{1} {1}{1}{1} {2}{11} {11}{11} {2}{13} {11}{22}
{1}{1}{2} {1}{1}{11} {3}{12} {12}{12}
{1}{2}{1} {1}{1}{1}{1} {1}{2}{3} {2}{112}
{2}{1}{1} {1}{3}{2} {22}{11}
{2}{1}{3} {1}{1}{22}
{2}{3}{1} {1}{2}{12}
{3}{1}{2} {2}{1}{12}
{3}{2}{1} {2}{2}{11}
{1}{1}{2}{2}
{1}{2}{1}{2}
{1}{2}{2}{1}
{2}{1}{1}{2}
{2}{1}{2}{1}
{2}{2}{1}{1}
MATHEMATICA
sps[{}]:={{}}; sps[set:{i_, ___}]:=Join@@Function[s, Prepend[#, s]&/@sps[Complement[set, s]]]/@Cases[Subsets[set], {i, ___}];
mps[set_]:=Union[Sort[Sort/@(#/.x_Integer:>set[[x]])]&/@sps[Range[Length[set]]]];
nrmptn[n_]:=Join@@MapIndexed[Table[#2[[1]], {#1}]&, If[n==1, {}, Flatten[Cases[FactorInteger[n]//Reverse, {p_, k_}:>Table[PrimePi[p], {k}]]]]];
Table[Sum[Times@@Factorial/@Length/@Split[Sort[Length/@mtn, Greater]]/Times@@Factorial/@Length/@Split[mtn], {mtn, mps[nrmptn[n]]}], {n, 30}]
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Gus Wiseman, Nov 19 2018
STATUS
approved