Number of k < 10^n such that A047988(k) = 4.

A213533

Number of k < 10^n such that A047988(k) = 4.

Terms

    a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =3a(7) =19a(8) =183a(9) =1601a(10) =14598a(11) =130117

External references