a(n) = T(n,n-4), T given by A026584. Also a(n) = number of integer strings s(0),...,s(n) counted by T, such that s(n)=4.

A026589

a(n) = T(n,n-4), T given by A026584. Also a(n) = number of integer strings s(0),...,s(n) counted by T, such that s(n)=4.

Terms

    a(0) =1a(1) =2a(2) =9a(3) =22a(4) =69a(5) =178a(6) =497a(7) =1294a(8) =3452a(9) =8964a(10) =23430a(11) =60556a(12) =156663a(13) =403214a(14) =1037191a(15) =2660978a(16) =6821200a(17) =17459732a(18) =44657246a(19) =114117628a(20) =291449047a(21) =743904326a(22) =1897956899a(23) =4840429962a(24) =12340947855a(25) =31455453822a(26) =80158533099

External references