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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.

A271271 Number of set partitions of [n] such that at least one pair of consecutive blocks (b,b+1) exists having no pair of consecutive numbers (i,i+1) with i member of b and i+1 member of b+1.

Table of values

n a(n)
0 0
1 0
2 0
3 0
4 1
5 9
6 58
7 341
8 1983
9 11776
10 72345
11 462173
12 3075894
13 21330762
14 154050330
15 1157493707
16 9037925277
17 73244123107
18 615295131046
19 5351329029624
20 48126530239366
21 447043890866154
22 4284293705043796
23 42317095568379559
24 430355360965092107
25 4501973706497500364

List of values

[0, 0, 0, 0, 1, 9, 58, 341, 1983, 11776, 72345, 462173, 3075894, 21330762, 154050330, 1157493707, 9037925277, 73244123107, 615295131046, 5351329029624, 48126530239366, 447043890866154, 4284293705043796, 42317095568379559, 430355360965092107, 4501973706497500364]

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

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