All finite-dimensional indecomposable solvable Lie algebras L(n,f), having
the triangular algebra T(n) as their nilradical, are constructed. The number of
nonnilpotent elements f in L(n,f) satisfies 1≤f≤n−1 and the
dimension of the Lie algebra is dimL(n,f)=f+1/2n(n−1)