Number of nonnegative integer matrices with 2 distinct columns and any number of distinct nonzero rows with each column sum being n and rows in decreasing lexicographic order.

A331317

Number of nonnegative integer matrices with 2 distinct columns and any number of distinct nonzero rows with each column sum being n and rows in decreasing lexicographic order.

Terms

    a(0) =0a(1) =1a(2) =4a(3) =15a(4) =44a(5) =120a(6) =319a(7) =804a(8) =1960a(9) =4652a(10) =10782a(11) =24435a(12) =54329a(13) =118663a(14) =254969a(15) =539825a(16) =1127247a(17) =2323811a(18) =4733634a(19) =9535025a(20) =19005218a(21) =37507726a(22) =73333405a(23) =142112298a(24) =273092198a(25) =520612163a(26) =984943887a(27) =1849920530a(28) =3450475858a(29) =6393203485

External references