a(n) = number of integer strings s(0),...,s(n) counted by array T in A026374 that have s(n)=3; also a(n) = T(2n-1,n-2).

A026379

a(n) = number of integer strings s(0),...,s(n) counted by array T in A026374 that have s(n)=3; also a(n) = T(2n-1,n-2).

Terms

    a(0) =1a(1) =7a(2) =39a(3) =202a(4) =1015a(5) =5028a(6) =24731a(7) =121208a(8) =593019a(9) =2899335a(10) =14173401a(11) =69301422a(12) =338990145a(13) =1659037695a(14) =8124085575a(15) =39806373880a(16) =195160896835a(17) =957396540285

External references