A239258 Number of partitions of 2n having twice as many odd parts as even.

1, 0, 1, 2, 5, 8, 15, 23, 39, 59, 94, 140, 216, 316, 472, 682, 994, 1414, 2022, 2837, 3989, 5530, 7663, 10504, 14381, 19509, 26417, 35510, 47618, 63461, 84365, 111553, 147126, 193144, 252892, 329773, 428931, 555852, 718547, 925795, 1189946, 1524863, 1949540

Offset

0,4

Links

Table of n, a(n) for n=0..42.

Example

a(5) counts these 8 partitions of 10:  811, 721, 631, 541, 532, 433, 421111, 322111.

Mathematica

p[n_] := p[n] = Select[IntegerPartitions[2 n], Count[#, _?OddQ] == 2*Count[#, _?EvenQ] &]; t = Table[p[n], {n, 0, 8}] (* shows the partitions *); TableForm[t] (* partitions, vertical format *)
t1 = Table[Length[p[n]], {n, 0, 60}] (* A239258 *)
(* Peter J. C. Moses, Mar 10 2014 *)

Crossrefs

Cf. A239004.

Sequence in context: A349796 A058884 A073335 * A362864 A309551 A309625

Adjacent sequences: A239255 A239256 A239257 * A239259 A239260 A239261

Keyword

nonn,easy

Author

Clark Kimberling, Mar 13 2014

Extensions

More terms from Alois P. Heinz, Mar 15 2014

Status

approved