cp's OEIS Frontend

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.

Showing 1-3 of 3 results.

A130167 Another version of triangle in A127743.

Original entry on oeis.org

1, 0, 1, 0, 1, 1, 0, 2, 2, 1, 0, 6, 5, 3, 1, 0, 22, 16, 9, 4, 1, 0, 92, 60, 31, 14, 5, 1, 0, 426, 252, 120, 52, 20, 6, 1, 0, 2146, 1160, 510, 209, 80, 27, 7, 1, 0, 11624, 5776, 2348, 904, 335, 116, 35, 8, 1, 0, 67146, 30832, 11610, 4184, 1481, 507, 161, 44, 9, 1
Offset: 0

Views

Author

Philippe Deléham, Aug 03 2007

Keywords

Comments

Triangle T(n,k), 0 <= k <= n, read by rows given by [0,1,1,2,1,3,1,4,1,5,1,6,1,...] DELTA [1,0,0,0,0,0,0,...] where DELTA is the operator defined in A084938.
Modulo 2, this sequence gives A106344. - Philippe Deléham, Dec 18 2008
A154380*A130595 as infinite lower triangular matrices. - Philippe Deléham, Jan 13 2009

Examples

			Triangle begins:
  1;
  0,  1;
  0,  1,  1;
  0,  2,  2,  1;
  0,  6,  5,  3,  1;
  0, 22, 16,  9,  4,  1;
  0, 92, 60, 31, 14,  5,  1; ...
		

Crossrefs

Cf. A074664.

Formula

Sum_{k=0..n} T(n,k) = A000110(n).

A179313 Triangle T(n,k) read by rows: product of the compositorial weight of the k-th partition of n times A074664(.) applied to each part.

Original entry on oeis.org

1, 1, 1, 2, 2, 1, 6, 4, 1, 3, 1, 22, 12, 4, 6, 3, 4, 1, 92, 44, 12, 4, 18, 12, 1, 8, 6, 5, 1, 426, 184, 44, 24, 66, 36, 12, 6, 24, 24, 4, 10, 10, 6, 1, 2146, 852, 184, 88, 36, 276, 132, 72, 18, 12, 88, 72, 24, 24, 1, 30, 40, 10, 12, 15, 7, 1, 11624, 4292, 852, 368, 264, 1278, 552
Offset: 1

Views

Author

Alford Arnold, Jul 11 2010

Keywords

Comments

Row n has A000041(n) entries. T(n,k) is the product of A074664(a_i) over all parts a_i
multiplied by the compositorial weight A048996(n,k) of the k-th partition (Abramowitz-Stegun order)
of n = sum_i a_i.
Summing also over the partitions with a common number of parts would create A127743.
In row n=4, for example, the partitions 3+1 and 2+2, each with 2 parts, are represented by
T(4,2)=4 and T(4,3)= 1 here, and the sum 4+1=5 of the entries is the single entry A127743(4,.).
In this sense, the table is a refinement of A127743.

Examples

			T(6,3) represents the 3rd partition of 6, namely 2+4. A074664(2)*A074664(4) = 1*6 is multiplied
by the weight A048996([2,4]) = 2!/1!/1! =2, and T(6,3) =1*6*2=12.
T(6,5) represents the 5th partition of 6, namely 1+1+4. A074664(1)*A074664(1)*A074664(4) = 1*1*6 is multiplied
by the weight A048996([1,1,4]) = 3!/2!/1! =3, and T(6,5) =1*1*6*3.
T(7,6) represents the 6th partition of 7, namely 1+2+4. A074664(1)*A074664(2)*A074664(4) = 1*1*6 is multiplied
the weight A048996([1,2,4]) = 3!/1!/1!/1! =6, and T(7,6) =1*1*6*6.
The triangle starts
1;
1,1;
2,2,1;
6,4,1,3,1;
22,12,4,6,3,4,1;
92,44,12,4,18,12,1,8,6,5,1;
426,184,44,24,66,36,12,6,24,24,4,10,10,6,1;
		

References

  • M. Abramowitz and I. A. Stegun, Handbook of Mathematical Functions, p. 831

Crossrefs

Formula

T(n,k) = A048996(n,k) * A179380(n,k).
sum_{k=1..A000041(n)} T(n,k) = A000110(n).

Extensions

Edited and extended by R. J. Mathar, Jul 16 2010

A127745 Counts Bell numbers (except for Catalans) associated with the partition number [n].

Original entry on oeis.org

0, 0, 0, 1, 8, 50, 294, 1717, 10194, 62284, 394346, 2597266, 17827166, 127575414, 951411752, 7386583917, 59623674472, 499648882838, 4340548090590, 39033489125836, 362871600781796, 3482858492844510, 34471940635650958, 351444263328831458
Offset: 1

Views

Author

Alford Arnold, Feb 25 2007

Keywords

Comments

A074664 counts the Bell Numbers associated with the partition number [n]. A000108 counts the corresponding Catalan numbers and here we count the remaining Bell numbers associated with the partition number [n].

Examples

			There are 15 Bell objects when n = 4, 14 are also Catalans so a(4) = 1.
There are 52 Bell objects when n = 5, 42 are also Catalans; we know that 5 = 4+1 = 1+4 which accounts for two of the non-Catalan Bells so, a(5) = 52 - 42 - 2 = 8.
		

Crossrefs

Formula

a(n) = A074664(n) - A000108(n-1)
Showing 1-3 of 3 results.