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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.

A084771 Coefficients of expansion of 1/sqrt(1 - 10*x + 9*x^2); also, a(n) is the central coefficient of (1 + 5*x + 4*x^2)^n.

Table of values

n a(n)
0 1
1 5
2 33
3 245
4 1921
5 15525
6 127905
7 1067925
8 9004545
9 76499525
10 653808673
11 5614995765
12 48416454529
13 418895174885
14 3634723102113
15 31616937184725
16 275621102802945
17 2407331941640325
18 21061836725455905
19 184550106298084725

List of values

[1, 5, 33, 245, 1921, 15525, 127905, 1067925, 9004545, 76499525, 653808673, 5614995765, 48416454529, 418895174885, 3634723102113, 31616937184725, 275621102802945, 2407331941640325, 21061836725455905, 184550106298084725]

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

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