S(n,n) + S(n-1,n-2) + S(n-2,n-4) + ... + S(n-k+1,n-2k+2), where k = [ (n+1)/2 ] and S(i,j) are Stirling numbers of second kind.

A024428

S(n,n) + S(n-1,n-2) + S(n-2,n-4) + ... + S(n-k+1,n-2k+2), where k = [ (n+1)/2 ] and S(i,j) are Stirling numbers of second kind.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =4a(4) =8a(5) =18a(6) =42a(7) =102a(8) =260a(9) =684a(10) =1860a(11) =5216a(12) =15020a(13) =44388a(14) =134336a(15) =415672a(16) =1313696a(17) =4234904a(18) =13911528a(19) =46525992a(20) =158279872a(21) =547327904a(22) =1922455440a(23) =6854491840a(24) =24794405328a(25) =90940138256a(26) =338037825952

External references