Sum of the forward and reverse concatenations of 1 to n.

A078262

Sum of the forward and reverse concatenations of 1 to n.

Terms

    a(0) =2a(1) =33a(2) =444a(3) =5555a(4) =66666a(5) =777777a(6) =8888888a(7) =99999999a(8) =1111111110a(9) =23333333231

External references