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

A026378

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

Terms

    a(0) =1a(1) =4a(2) =17a(3) =75a(4) =339a(5) =1558a(6) =7247a(7) =34016a(8) =160795a(9) =764388a(10) =3650571a(11) =17501619a(12) =84179877a(13) =406020930a(14) =1963073865a(15) =9511333155a(16) =46169418195a(17) =224484046660

External references