Concatenation of sequence (1, 2, ..., floor((n-1)/2), floor(n/2), floor(n/2)-1, ..., 1) for n >= 1.

A007907

Concatenation of sequence (1, 2, ..., floor((n-1)/2), floor(n/2), floor(n/2)-1, ..., 1) for n >= 1.

Terms

    a(0) =1a(1) =11a(2) =121a(3) =1221a(4) =12321a(5) =123321a(6) =1234321a(7) =12344321a(8) =123454321a(9) =1234554321a(10) =12345654321a(11) =123456654321

External references