a(n) = T(n,n-3), T given by A026536. Also number of integer strings s(0), ..., s(n), counted by T, such that s(n) = 3.

A026540

a(n) = T(n,n-3), T given by A026536. Also number of integer strings s(0), ..., s(n), counted by T, such that s(n) = 3.

Terms

    a(0) =1a(1) =2a(2) =6a(3) =16a(4) =36a(5) =104a(6) =215a(7) =635a(8) =1275a(9) =3786a(10) =7518a(11) =22344a(12) =44170a(13) =131264a(14) =259002a(15) =769578a(16) =1517418a(17) =4508580a(18) =8888495a(19) =26412001a(20) =52077234a(21) =154773696a(22) =305257251a(23) =907432695a(24) =1790353357a(25) =5323519838a(26) =10507386918a(27) =31251588060

External references