Number of 2-compositions of n containing at least one 0 entry. A 2-composition of n is a nonnegative matrix with two rows, such that each column has at least one nonzero entry and whose entries sum up to n.
A181367
Number of 2-compositions of n containing at least one 0 entry. A 2-composition of n is a nonnegative matrix with two rows, such that each column has at least one nonzero entry and whose entries sum up to n.
Terms
- a(0) =2a(1) =6a(2) =22a(3) =78a(4) =272a(5) =940a(6) =3232a(7) =11080a(8) =37920a(9) =129648a(10) =443008a(11) =1513248a(12) =5168000a(13) =17647552a(14) =60258304a(15) =205746304a(16) =702484992a(17) =2398480128a(18) =8189016064a(19) =27959235072a(20) =95459170304a(21) =325918735360
External references
- oeis: A181367