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.

A134151 Triangle of numbers obtained from the partition array A134150.

Original entry on oeis.org

1, 4, 1, 28, 4, 1, 280, 44, 4, 1, 3640, 392, 44, 4, 1, 58240, 5544, 456, 44, 4, 1, 1106560, 80640, 5992, 456, 44, 4, 1, 24344320, 1519840, 88256, 6248, 456, 44, 4, 1, 608608000, 31420480, 1631392, 90048, 6248, 456, 44, 4, 1, 17041024000, 766525760, 33293120
Offset: 1

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Author

Wolfdieter Lang Nov 13 2007

Keywords

Comments

This triangle is named S2(4)'.
In the same manner the unsigned Lah triangle A008297 is obtained from the partition array A130561.

Examples

			[1]; [4,1]; [28,4,1]; [280,44,4,1]; [3640,392,44,4,1];...
		

Crossrefs

Cf. A134152 (row sums). A134272 (alternating row sums).
Cf. A134146 (S2(3)' triangle).

Formula

a(n,m)=sum(product(S2(4;j,1)^e(n,m,q,j),j=1..n),q=1..p(n,m)) if n>=m>=1, else 0. Here p(n,m)=A008284(n,m), the number of m parts partitions of n and e(n,m,q,j) is the exponent of j in the q-th m part partition of n. S2(4;j,1)= A007559(j) = A035469(j,1) = (3*j-2)!!!.

A134150 A certain partition array in Abramowitz-Stegun order (A-St order), called M_3(4)/M_3.

Original entry on oeis.org

1, 4, 1, 28, 4, 1, 280, 28, 16, 4, 1, 3640, 280, 112, 28, 16, 4, 1, 58240, 3640, 1120, 784, 280, 112, 64, 28, 16, 4, 1, 1106560, 58240, 14560, 7840, 3640, 1120, 784, 448, 280, 112, 64, 28, 16, 4, 1, 24344320, 1106560, 232960, 101920, 78400, 58240, 14560, 7840
Offset: 1

Views

Author

Wolfdieter Lang, Nov 13 2007

Keywords

Comments

The sequence of row lengths is A000041 (partition numbers) [1, 2, 3, 5, 7, 11, 15, 22, 30, 42, ...].
For the A-St order of partitions see the Abramowitz-Stegun reference given in A117506.
Partition number array M_3(4) = A134149 with each entry divided by the corresponding one of the partition number array M_3 = M_3(1) = A036040; in short, M_3(4)/M_3.

Examples

			Triangle begins:
  [1];
  [4,1];
  [28,4,1];
  [280,28,16,4,1];
  [3640,280,112,28,16,4,1];
  ...
a(4,3)=16 from the third (k=3) partition (2^2) of 4: (4)^2 = 16, because S2(4,2,1) = 4!! = 4*1 = 4.
		

Crossrefs

Cf. A134145 (M_3(3)/M_3 array).
Cf. A134152 (row sums, also of triangle A134151).

Formula

a(n,k) = Product_{j=1..n} S2(4,j,1)^e(n,k,j) with S2(4,n,1) = A035469(n,1) = A007559(n) = (3*n-2)!!! and with the exponent e(n,k,j) of j in the k-th partition of n in the A-St ordering of the partitions of n.
a(n,k) = A134149(n,k)/A036040(n,k) (division of partition arrays M_3(4) by M_3).

A134272 Alternating row sums of triangle A134151.

Original entry on oeis.org

1, 3, 25, 239, 3289, 53111, 1031497, 22906903, 578734697, 16306214743, 508360540457, 17354157283287, 644314385719593, 25842490815894231, 1113789927340848937, 51332921853722842327, 2519491205735072674601
Offset: 1

Views

Author

Wolfdieter Lang, Nov 13 2007

Keywords

Crossrefs

Cf. A134152 (row sums of triangle A134151).

Formula

a(n) = Sum_{m=1..n} A134151(n,m)*(-1)^(m-1), n>=1.
Showing 1-3 of 3 results.