Stirling numbers of the first kind: s(n+2, n).

Terms

a(0) =0a(1) =2a(2) =11a(3) =35a(4) =85a(5) =175a(6) =322a(7) =546a(8) =870a(9) =1320a(10) =1925a(11) =2717a(12) =3731a(13) =5005a(14) =6580a(15) =8500a(16) =10812a(17) =13566a(18) =16815a(19) =20615a(20) =25025a(21) =30107a(22) =35926a(23) =42550a(24) =50050a(25) =58500a(26) =67977a(27) =78561a(28) =90335a(29) =103385