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.

A084609 Coefficients of 1/sqrt(1-4*x-8*x^2); also, a(n) is the central coefficient of (1+2*x+3*x^2)^n.

Table of values

n a(n)
0 1
1 2
2 10
3 44
4 214
5 1052
6 5284
7 26840
8 137638
9 710828
10 3692140
11 19266920
12 100932220
13 530479640
14 2795917960
15 14771797424
16 78210099718
17 414862155980
18 2204273582236
19 11729283976136
20 62496686731924
21 333400654676168

List of values

[1, 2, 10, 44, 214, 1052, 5284, 26840, 137638, 710828, 3692140, 19266920, 100932220, 530479640, 2795917960, 14771797424, 78210099718, 414862155980, 2204273582236, 11729283976136, 62496686731924, 333400654676168]

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

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