a(n) is the number of terms in A330418 with exactly n digits.

Terms

a(0) =1a(1) =0a(2) =1a(3) =2a(4) =9a(5) =22a(6) =109a(7) =390a(8) =2249a(9) =10006a(10) =53540a(11) =207218a(12) =967733a(13) =3587686a(14) =14902072a(15) =56388126a(16) =220066307a(17) =867528322a(18) =3324603126a(19) =13719108983