Construct a triangle with centered rows in which row n contains n copies of n; form the componentwise sum of the first n rows and concatenate these decimal numbers to get a(n).

A210257

Construct a triangle with centered rows in which row n contains n copies of n; form the componentwise sum of the first n rows and concatenate these decimal numbers to get a(n).

Terms

    a(0) =1a(1) =212a(2) =32423a(3) =4364634a(4) =548696845

External references