a(n) is the number of partitions of n into at most 3 parts; also partitions of n+3 in which the greatest part is 3; also number of unlabeled multigraphs with 3 nodes and n edges.
A001399
a(n) is the number of partitions of n into at most 3 parts; also partitions of n+3 in which the greatest part is 3; also number of unlabeled multigraphs with 3 nodes and n edges.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =3a(4) =4a(5) =5a(6) =7a(7) =8a(8) =10a(9) =12a(10) =14a(11) =16a(12) =19a(13) =21a(14) =24a(15) =27a(16) =30a(17) =33a(18) =37a(19) =40a(20) =44a(21) =48a(22) =52a(23) =56a(24) =61a(25) =65a(26) =70a(27) =75a(28) =80a(29) =85
External references
- oeis: A001399