login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A274841 Number of set partitions of [n] such that the difference between each element and its block index is a multiple of eight. 2
1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 19, 38, 73, 136, 247, 438, 757, 1268, 3303, 7883, 17801, 38745, 82179, 170907, 349341, 700517, 2066512, 5768089, 15386070, 39563059, 98692628, 239843745, 569063602, 1318211431, 4290275275, 13443268926 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,10

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..902

Wikipedia, Partition of a set

EXAMPLE

a(8) = 1: 1|2|3|4|5|6|7|8.

a(9) = 2: 19|2|3|4|5|6|7|8, 1|2|3|4|5|6|7|8|9.

a(10) = 3: 19|2(10)|3|4|5|6|7|8, 1|2(10)|3|4|5|6|7|8|9, 1|2|3|4|5|6|7|8|9|(10).

MAPLE

b:= proc(n, m, t) option remember; `if`(n=0, 1,

     add(`if`(irem(j-t, 8)=0, b(n-1, max(m, j),

              irem(t+1, 8)), 0), j=1..m+1))

    end:

a:= n-> b(n, 0, 1):

seq(a(n), n=0..45);

MATHEMATICA

b[n_, m_, t_] := b[n, m, t] = If[n == 0, 1, Sum[If[Mod[j - t, 8] == 0, b[n - 1, Max[m, j], Mod[t + 1, 8]], 0], {j, 1, m + 1}]];

a[n_] := b[n, 0, 1];

Table[a[n], {n, 0, 45}] (* Jean-Fran├žois Alcover, May 15 2018, after Alois P. Heinz *)

CROSSREFS

Column k=8 of A274835.

Sequence in context: A051885 A227378 A226637 * A247227 A048410 A341161

Adjacent sequences:  A274838 A274839 A274840 * A274842 A274843 A274844

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Jul 08 2016

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 21 06:36 EDT 2022. Contains 353889 sequences. (Running on oeis4.)