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.

A212777 Half the number of 0..3 arrays of length n+2 with second differences nonzero.

Table of values

n a(n)
1 28
2 99
3 350
4 1238
5 4379
6 15490
7 54793
8 193821
9 685609
10 2425226
11 8578828
12 30346157
13 107344412
14 379712753
15 1343169821
16 4751236703
17 16806698494
18 59450861306
19 210297394895
20 743891565706
21 2631390949017
22 9308101672049
23 32925839761497

List of values

[28, 99, 350, 1238, 4379, 15490, 54793, 193821, 685609, 2425226, 8578828, 30346157, 107344412, 379712753, 1343169821, 4751236703, 16806698494, 59450861306, 210297394895, 743891565706, 2631390949017, 9308101672049, 32925839761497]