2*Sum(floor(C(n,w)/w),w=1..n/2-1)+floor(C(n,n/2)/(n/2)) if n is even, otherwise 2*Sum(floor(C(n,w)/w),w=1..(n-1)/2).

A085573

2*Sum(floor(C(n,w)/w),w=1..n/2-1)+floor(C(n,n/2)/(n/2)) if n is even, otherwise 2*Sum(floor(C(n,w)/w),w=1..(n-1)/2).

Terms

    a(0) =2a(1) =6a(2) =11a(3) =20a(4) =32a(5) =56a(6) =97a(7) =172a(8) =298a(9) =534a(10) =952a(11) =1736a(12) =3150a(13) =5824a(14) =10724a(15) =20042a(16) =37308a(17) =70304a(18) =131971a(19) =250308a(20) =473020a(21) =901872a(22) =1713596a(23) =3281122a(24) =6262254a(25) =12033330a(26) =23053047a(27) =44431308a(28) =85393280a(29) =165008114

External references