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.

A283678 Number of possible draws of 2n pairs of consecutive cards from a set of 4n + 1 cards, so that the card that initially occupies the central position is not selected.

Table of values

n a(n)
0 1
1 2
2 54
3 4500
4 771750
5 225042300
6 99843767100
7 62673358948200
8 52880646612543750
9 57733914846094987500
10 79199384385873103852500
11 133357363417740148141455000
12 270426506783940730406180497500
13 650063718230626755784087734375000
14 1827886309419060919156885553671875000

List of values

[1, 2, 54, 4500, 771750, 225042300, 99843767100, 62673358948200, 52880646612543750, 57733914846094987500, 79199384385873103852500, 133357363417740148141455000, 270426506783940730406180497500, 650063718230626755784087734375000, 1827886309419060919156885553671875000]

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

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