login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A240306
Number of partitions p of n such that (maximal multiplicity of the parts of p) <= (number of distinct parts of p).
4
1, 1, 1, 2, 3, 5, 6, 9, 13, 17, 25, 33, 44, 59, 76, 100, 131, 169, 212, 278, 352, 442, 555, 703, 871, 1088, 1342, 1664, 2046, 2517, 3064, 3758, 4574, 5548, 6718, 8119, 9797, 11784, 14150, 16935, 20263, 24179, 28798, 34237, 40677, 48122, 57008, 67291, 79400
OFFSET
0,4
FORMULA
a(n) = A240305(n) + A239964(n) for n >= 0.
a(n) + A240308(n) = A000041(n) for n >= 0.
EXAMPLE
a(6) counts these 6 partitions: 6, 51, 42, 411, 321, 2211.
MATHEMATICA
z = 60; f[n_] := f[n] = IntegerPartitions[n]; m[p_] := Max[Map[Length, Split[p]]] (* maximal multiplicity *); d[p_] := d[p] = Length[DeleteDuplicates[p]] (* number of distinct terms *)
t1 = Table[Count[f[n], p_ /; m[p] < d[p]], {n, 0, z}] (* A240305 *)
t2 = Table[Count[f[n], p_ /; m[p] <= d[p]], {n, 0, z}] (* A240306 *)
t3 = Table[Count[f[n], p_ /; m[p] == d[p]], {n, 0, z}] (* A239964 *)
t4 = Table[Count[f[n], p_ /; m[p] >= d[p]], {n, 0, z}] (* A240308 *)
t5 = Table[Count[f[n], p_ /; m[p] > d[p]], {n, 0, z}] (* A240309 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Apr 05 2014
STATUS
approved