A035539 Number of partitions of n with equal nonzero number of parts congruent to each of 1 and 2 (mod 3)

0, 0, 0, 1, 0, 0, 4, 0, 0, 11, 0, 0, 27, 0, 0, 59, 0, 0, 123, 0, 0, 241, 0, 0, 458, 0, 0, 838, 0, 0, 1498, 0, 0, 2608, 0, 0, 4459, 0, 0, 7473, 0, 0, 12339, 0, 0, 20058, 0, 0, 32197, 0, 0, 51027, 0, 0, 80003, 0, 0, 124092, 0, 0, 190683, 0, 0, 290322, 0, 0, 438392, 0, 0, 656681, 0, 0

Offset

0,7

Links

Table of n, a(n) for n=0..71.

Mathematica

equalQ[partit_] := With[{t = Total[Switch[Mod[#, 3], 0, {1, 0, 0}, 1, {0, 1, 0}, 2, {0, 0, 1}]& /@ partit]}, t[[2]] > 0 && t[[2]] == t[[3]]]; a[n_] := If[Mod[n, 3] != 0, 0, Select[IntegerPartitions[n], equalQ] // Length]; a[0] = 0; Table[an = a[n]; Print["a(", n, ") = ", an]; an, {n, 0, 71}] (* Jean-François Alcover, Dec 07 2016 *)

Crossrefs

Cf. A035593.

Sequence in context: A272626 A271910 A249346 * A178517 A049207 A092219

Adjacent sequences: A035536 A035537 A035538 * A035540 A035541 A035542

Keyword

nonn

Author

Olivier Gérard

Status

approved