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.

A084778 a(n) = sum of absolute-valued coefficients of (1+2*x-3*x^2)^n.

Table of values

n a(n)
0 1
1 6
2 28
3 128
4 660
5 3016
6 13108
7 64112
8 304068
9 1332992
10 6514356
11 29341384
12 131904528
13 623547112
14 2990903464
15 13436119424
16 61647598484
17 284398511848
18 1302463169256
19 6195158123688
20 28653898573420
21 130138400720504

List of values

[1, 6, 28, 128, 660, 3016, 13108, 64112, 304068, 1332992, 6514356, 29341384, 131904528, 623547112, 2990903464, 13436119424, 61647598484, 284398511848, 1302463169256, 6195158123688, 28653898573420, 130138400720504]

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

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