a(n) = floor(n*exp(n)).

Terms

a(0) =0a(1) =2a(2) =14a(3) =60a(4) =218a(5) =742a(6) =2420a(7) =7676a(8) =23847a(9) =72927a(10) =220264a(11) =658615a(12) =1953057a(13) =5751374a(14) =16836459a(15) =49035260a(16) =142177768a(17) =410634196a(18) =1181879444a(19) =3391163718a(20) =9703303908a(21) =27695130424a(22) =78868082614a(23) =224130479263a(24) =635738931116