A241086 Number of partitions p of n into distinct parts such that max(p) <= 2*(number of parts of p).
0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 4, 4, 5, 5, 6, 7, 8, 9, 11, 12, 14, 15, 17, 19, 21, 24, 27, 31, 34, 38, 42, 47, 51, 57, 62, 70, 77, 85, 93, 104, 114, 125, 137, 150, 164, 180, 196, 214, 234, 255, 279, 304, 332, 360, 393, 426, 464, 502, 545, 589, 640, 691, 749
Offset: 0
Programs
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Mathematica
z = 40; f[n_] := f[n] = Select[IntegerPartitions[n], Max[Length /@ Split@#] == 1 &]; Table[Count[f[n], p_ /; Max[p] < 2*Length[p]], {n, 0, z}] (* A241085 *) Table[Count[f[n], p_ /; Max[p] <= 2*Length[p]], {n, 0, z}] (* A241086 *) Table[Count[f[n], p_ /; Max[p] == 2*Length[p]], {n, 0, z}] (* A241087 *) Table[Count[f[n], p_ /; Max[p] >= 2*Length[p]], {n, 0, z}] (* A241088 *) Table[Count[f[n], p_ /; Max[p] > 2*Length[p]], {n, 0, z}] (* A241089 *)
Formula
a(15) counts these 7 partitions: 8421, 7521, 7431, 654, 6531, 6432, 54321.