a(n) = n 2's sandwiched between two 1's.

A132583

a(n) = n 2's sandwiched between two 1's.

Terms

    a(0) =11a(1) =121a(2) =1221a(3) =12221a(4) =122221a(5) =1222221a(6) =12222221a(7) =122222221a(8) =1222222221a(9) =12222222221a(10) =122222222221

External references