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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.

A268429 Number of North-East lattice paths from (0,0) to (n,n) that bounce off the diagonal y = x to the right exactly once.

Table of values

n a(n)
2 1
3 4
4 16
5 62
6 238
7 910
8 3475
9 13270
10 50707
11 193948
12 742659
13 2847126
14 10928009
15 41993692
16 161555008
17 622201838
18 2398811962
19 9257512318
20 35760612784
21 138263710226
22 535038428936
23 2072130742074
24 8031333322206
25 31151602276002
26 120915026597458
27 469648731423190
28 1825348333058230
29 7098811400187410
30 27623655321103718

List of values

[1, 4, 16, 62, 238, 910, 3475, 13270, 50707, 193948, 742659, 2847126, 10928009, 41993692, 161555008, 622201838, 2398811962, 9257512318, 35760612784, 138263710226, 535038428936, 2072130742074, 8031333322206, 31151602276002, 120915026597458, 469648731423190, 1825348333058230, 7098811400187410, 27623655321103718]

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

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