cp's OEIS Frontend

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.

A358439 Number of even digits necessary to write all positive n-digit integers.

Table of values

n a(n)
1 4
2 85
3 1300
4 17500
5 220000
6 2650000
7 31000000
8 355000000
9 4000000000
10 44500000000
11 490000000000
12 5350000000000
13 58000000000000
14 625000000000000
15 6700000000000000
16 71500000000000000
17 760000000000000000
18 8050000000000000000
19 85000000000000000000
20 895000000000000000000

List of values

[4, 85, 1300, 17500, 220000, 2650000, 31000000, 355000000, 4000000000, 44500000000, 490000000000, 5350000000000, 58000000000000, 625000000000000, 6700000000000000, 71500000000000000, 760000000000000000, 8050000000000000000, 85000000000000000000, 895000000000000000000]

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

Content is available under The OEIS End-User License Agreement.