login
This site is supported by donations to The OEIS Foundation.

 

Logo

Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A270236 Triangle T(n,p) read by rows: the number of occurrences of p in the restricted growth functions of length n. 16
1, 3, 1, 9, 5, 1, 30, 21, 8, 1, 112, 88, 47, 12, 1, 463, 387, 253, 97, 17, 1, 2095, 1816, 1345, 675, 184, 23, 1, 10279, 9123, 7304, 4418, 1641, 324, 30, 1, 54267, 48971, 41193, 28396, 13276, 3645, 536, 38, 1, 306298, 279855, 243152, 183615, 102244, 36223, 7473, 842, 47, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The RG functions used here are defined by f(1)=1, f(j) <= 1+max_{i<j} f(i).

T(n,p) is the number of elements in the p-th subset in all set partitions of [n]. [Joerg Arndt, Mar 14 2016]

LINKS

Alois P. Heinz, Rows n = 1..141, flattened

FORMULA

T(n,n)=1.

Conjecture: T(n,n-1) = 2+n*(n-1)/2 for n>1.

Conjecture: T(n+1,n-1) = 2+n*(n+1)*(3*n^2-5*n+26)/24 for n>1.

EXAMPLE

The two restricted growth functions of length 2 are (1,1) and (1,2). The 1 appears 3 times and the 2 once, so T(2,1)=3 and T(2,2)=1.

1;

3,1;

9,5,1;

30,21,8,1;

112,88,47,12,1;

463,387,253,97,17,1;

2095,1816,1345,675,184,23,1;

10279,9123,7304,4418,1641,324,30,1;

54267,48971,41193,28396,13276,3645,536,38,1;

306298,279855,243152,183615,102244,36223,7473,842,47,1;

1838320,1695902,1506521,1211936,770989,334751,90223,14303,1267,57,1;

11677867,10856879,9799547,8237223,5795889,2965654,995191,207186,25820, 1839,68,1;

MAPLE

b:= proc(n, m) option remember; `if`(n=0, [1, 0], add((p->

      [p[1], p[2]+p[1]*x^j])(b(n-1, max(m, j))), j=1..m+1))

    end:

T:= n-> (p-> seq(coeff(p, x, i), i=1..n))(b(n, 0)[2]):

seq(T(n), n=0..12);  # Alois P. Heinz, Mar 14 2016

MATHEMATICA

b[n_, m_] := b[n, m] = If[n == 0, {1, 0}, Sum[Function[p, {p[[1]], p[[2]] + p[[1]]*x^j}][b[n-1, Max[m, j]]], {j, 1, m+1}]];

T[n_] := Function[p, Table[Coefficient[p, x, i], {i, 1, n}]][b[n, 0][[2]] ]; Table[T[n], {n, 0, 12}] // Flatten (* Jean-Fran├žois Alcover, Apr 07 2016, after Alois P. Heinz *)

CROSSREFS

Cf. A070071 (row sums).

Column p=1-10 gives: A124427, A270494, A270495, A270496, A270497, A270498, A270499, A270500, A270501, A270502.

T(2n+1,n+1) gives A270529.

Cf. A000110, A185105, A285362, A286416.

Sequence in context: A005533 A112626 A050155 * A140714 A112932 A077895

Adjacent sequences:  A270233 A270234 A270235 * A270237 A270238 A270239

KEYWORD

nonn,tabl

AUTHOR

R. J. Mathar, Mar 13 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 | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 16 15:53 EST 2019. Contains 319195 sequences. (Running on oeis4.)