Number of nonequivalent 2-column nonnegative integer matrices with column sums n and any number of nonzero rows up to permutation of rows and columns.
A331722
Number of nonequivalent 2-column nonnegative integer matrices with column sums n and any number of nonzero rows up to permutation of rows and columns.
Terms
- a(0) =1a(1) =2a(2) =7a(3) =21a(4) =66a(5) =192a(6) =565a(7) =1579a(8) =4348a(9) =11582a(10) =30205a(11) =76736a(12) =191120a(13) =465920a(14) =1115572a(15) =2623885a(16) =6074353a(17) =13849021a(18) =31137381a(19) =69082779a(20) =151390617a(21) =327897173a(22) =702426987a(23) =1489108503a(24) =3125821257a(25) =6500086120a(26) =13396645887a(27) =27376083598a(28) =55490121271a(29) =111604327066
External references
- oeis: A331722