a(n) = n 7's sandwiched between two 1's.

A205087

a(n) = n 7's sandwiched between two 1's.

Terms

    a(0) =11a(1) =171a(2) =1771a(3) =17771a(4) =177771a(5) =1777771a(6) =17777771a(7) =177777771a(8) =1777777771a(9) =17777777771a(10) =177777777771

External references