a(n) = 2*(a(n-1) + (n-1)*a(n-2)) for n >= 2 with a(0) = 1.
A000898
a(n) = 2*(a(n-1) + (n-1)*a(n-2)) for n >= 2 with a(0) = 1.
Terms
- a(0) =1a(1) =2a(2) =6a(3) =20a(4) =76a(5) =312a(6) =1384a(7) =6512a(8) =32400a(9) =168992a(10) =921184a(11) =5222208a(12) =30710464a(13) =186753920a(14) =1171979904a(15) =7573069568a(16) =50305536256a(17) =342949298688
External references
- oeis: A000898