a(n) = A026568(n,n-1), also a(n) = number of integer strings s(0),...,s(n) counted by A026568 such that s(n)=1.

A026570

a(n) = A026568(n,n-1), also a(n) = number of integer strings s(0),...,s(n) counted by A026568 such that s(n)=1.

Terms

    a(0) =1a(1) =1a(2) =4a(3) =7a(4) =20a(5) =43a(6) =111a(7) =259a(8) =648a(9) =1565a(10) =3885a(11) =9533a(12) =23662a(13) =58547a(14) =145630a(15) =362151a(16) =903110a(17) =2253615a(18) =5633359a(19) =14094035a(20) =35304658a(21) =88511733a(22) =222115782a(23) =557819793a(24) =1401987930a(25) =3526066273a(26) =8874034647a(27) =22346581133a(28) =56304982154

External references