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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.

A322243 a(n) = A322242(n)^2, the square of the central coefficient in (1 + 3*x + 4x^2)^n.

Table of values

n a(n)
0 1
1 9
2 289
3 9801
4 370881
5 14768649
6 609546721
7 25795893321
8 1112301387649
9 48661046208009
10 2153525838773409
11 96206353829163081
12 4331637064535243841
13 196320612369490652169
14 8948100956521251936609
15 409841929215895450531401
16 18851871634769751620818689
17 870412126485504031282344969
18 40322236319029726815932366881
19 1873525179289326411511891685961
20 87284881539374630658475997415361

List of values

[1, 9, 289, 9801, 370881, 14768649, 609546721, 25795893321, 1112301387649, 48661046208009, 2153525838773409, 96206353829163081, 4331637064535243841, 196320612369490652169, 8948100956521251936609, 409841929215895450531401, 18851871634769751620818689, 870412126485504031282344969, 40322236319029726815932366881, 1873525179289326411511891685961, 87284881539374630658475997415361]

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

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