A129847 - cp's OEIS frontend

A129847 a(n) = number of set partitions of {1, 2, ..., n} whose blocks consist only of elements that differ by two or less (that is, have only the forms {i}, {i,i+1}, {i,i+2}, or {i,i+1,i+2}).

n	a(n)
0	1
1	1
2	2
3	5
4	10
5	20
6	42
7	87
8	179
9	370
10	765
11	1580
12	3264
13	6744
14	13933
15	28785
16	59470
17	122865
18	253838
19	524428
20	1083466
21	2238435
22	4624595
23	9554390
24	19739321
25	40781336
26	84254032
27	174068400
28	359624425
29	742982225
30	1534997482
31	3171296957
32	6551883314
33	13536157460

[1, 1, 2, 5, 10, 20, 42, 87, 179, 370, 765, 1580, 3264, 6744, 13933, 28785, 59470, 122865, 253838, 524428, 1083466, 2238435, 4624595, 9554390, 19739321, 40781336, 84254032, 174068400, 359624425, 742982225, 1534997482, 3171296957, 6551883314, 13536157460]

cp's OEIS Frontend

A129847 a(n) = number of set partitions of {1, 2, ..., n} whose blocks consist only of elements that differ by two or less (that is, have only the forms {i}, {i,i+1}, {i,i+2}, or {i,i+1,i+2}).

Table of values

List of values