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This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A019520 a(n) is the concatenation of the first n positive even numbers.

Table of values

n a(n)
1 2
2 24
3 246
4 2468
5 246810
6 24681012
7 2468101214
8 246810121416
9 24681012141618
10 2468101214161820
11 246810121416182022
12 24681012141618202224
13 2468101214161820222426
14 246810121416182022242628
15 24681012141618202224262830
16 2468101214161820222426283032

List of values

[2, 24, 246, 2468, 246810, 24681012, 2468101214, 246810121416, 24681012141618, 2468101214161820, 246810121416182022, 24681012141618202224, 2468101214161820222426, 246810121416182022242628, 24681012141618202224262830, 2468101214161820222426283032]

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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