longest common subsequences problem

[Ralf Stephan]

> now, (3*f(2*n)-f(2*n+2))/2 gives :
> 1,1,1,3,7,18,46,120,316,841,2257,6103,16611,45475,125139,..
> which is A026107 (see below)

Also (please add to database):

%Y A026107 First differences of A002026.
%Y A002026 Cf. A026107.