Number of twin Harshads, including overlaps, whose sum is prime and where the 2nd Harshad is <= 10^n.

A060291

Number of twin Harshads, including overlaps, whose sum is prime and where the 2nd Harshad is <= 10^n.

Terms

    a(0) =7a(1) =8a(2) =21a(3) =60a(4) =278a(5) =1520a(6) =9583a(7) =61835a(8) =419705a(9) =3023007a(10) =22597508

External references