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).

1, 212, 32423, 4364634, 548696845, 651081291281056, 7612101512161215101267, 87141218152016201518121478, 981614211824202520241821141689, 109181624212824302530242821241618910

Offset

1,2

Comments

A109242 may be constructed using a similar pyramid algorithm:

....1..........a(1) = 1

...1 1.........a(2) = 111

..1 1 1........a(3) = 11211

.1 1 1 1.......a(4) = 1122211

Links

Table of n, a(n) for n=1..10.

Example

...1................a(1) = 1
..2 2...............a(2) = 212
.3 3 3..............a(3) = 32423
4 4 4 4.............a(4) = 4364634

Crossrefs

Sequence in context: A332121 A083962 A007942 * A239045 A262657 A079794

Adjacent sequences: A210254 A210255 A210256 * A210258 A210259 A210260

Keyword

nonn,base

Author

Dave Durgin, Mar 19 2012

Extensions

Definition edited by N. J. A. Sloane, Jan 11 2020

Status

approved