Concatenation of the palindromic numbers (A002113) in increasing order up to the n-th term and then in decreasing order.

A261570

Concatenation of the palindromic numbers (A002113) in increasing order up to the n-th term and then in decreasing order.

Terms

    a(0) =1a(1) =121a(2) =12321a(3) =1234321a(4) =123454321a(5) =12345654321

External references