a(1) = 1, a(2) = 2, a(n) = a(1)*a(n-1) + a(2)*a(n-2) + ...+ a(n-2)*a(2) for n >= 3.

A014431

a(1) = 1, a(2) = 2, a(n) = a(1)*a(n-1) + a(2)*a(n-2) + ...+ a(n-2)*a(2) for n >= 3.

Terms

    a(0) =1a(1) =2a(2) =2a(3) =6a(4) =14a(5) =42a(6) =122a(7) =382a(8) =1206a(9) =3922a(10) =12914a(11) =43190a(12) =145950a(13) =498170a(14) =1714026a(15) =5940014a(16) =20712646a(17) =72623266a(18) =255875298a(19) =905477734a(20) =3216853294a(21) =11469069258a(22) =41023019098a(23) =147166210014a(24) =529374272470

External references