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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.

A386255 Number of words of length n over an infinite alphabet such that for any letter k appearing within a word the letter k appears at least k times and exactly one of each kind of letter is marked.

Table of values

n a(n)
0 1
1 1
2 4
3 15
4 64
5 325
6 1776
7 11179
8 72640
9 489969
10 3435580
11 26495491
12 221599104
13 1893705697
14 16145571820
15 138299146665
16 1241234863936
17 12033569772769
18 124055067568788
19 1303750295285563
20 13577876900409280
21 139418829477000801
22 1441311794301705964
23 15537427948684769425

List of values

[1, 1, 4, 15, 64, 325, 1776, 11179, 72640, 489969, 3435580, 26495491, 221599104, 1893705697, 16145571820, 138299146665, 1241234863936, 12033569772769, 124055067568788, 1303750295285563, 13577876900409280, 139418829477000801, 1441311794301705964, 15537427948684769425]

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

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