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.

A281946 Number of sequences of balls colored with at most n colors such that exactly two balls are of a color seen earlier in the sequence.

Table of values

n a(n)
1 1
2 16
3 195
4 2248
5 26245
6 318936
7 4082071
8 55289200
9 793525833
10 12063384640
11 194002619371
12 3294811981176
13 58980720557005
14 1110692723476168
15 21960340413007935
16 455018383693865056
17 9862401602086024081
18 223233406292824965360
19 5268151612376938762003
20 129425572759622914323880

List of values

[1, 16, 195, 2248, 26245, 318936, 4082071, 55289200, 793525833, 12063384640, 194002619371, 3294811981176, 58980720557005, 1110692723476168, 21960340413007935, 455018383693865056, 9862401602086024081, 223233406292824965360, 5268151612376938762003, 129425572759622914323880]

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

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