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 1-4 of 4 results.

A145359 Second column (m=2) of triangle A145357 (S1hat(6)).

Original entry on oeis.org

1, 6, 78, 588, 6804, 62496, 753984, 8273664, 109118016, 1408700160, 20697223680, 309818234880, 5100265336320, 87215844925440, 1605019401216000, 30898776106598400, 631358784683827200, 13503510009903513600, 303781522335363072000, 7137966147222822912000
Offset: 1

Views

Author

Wolfdieter Lang, Oct 17 2008

Keywords

Crossrefs

Cf. A145357, A001725 (first column), A145360 (third column).

Formula

a(n) = A145357(n+2,2), n>=0.

Extensions

Changed offset from 0 to 1 by Wolfdieter Lang, Nov 17 2008

A145358 Row sums of triangle A145357 and of array A145356.

Original entry on oeis.org

1, 7, 49, 421, 3697, 37933, 404341, 4841341, 61291861, 848268421, 12465197269, 197121724549, 3302727019621, 58876330343173, 1107627703783909, 21990846791015845, 458649487144877029, 10035575758396240549, 229687317927141716005, 5489966024995169233573
Offset: 1

Views

Author

Wolfdieter Lang, Oct 17 2008

Keywords

Crossrefs

Formula

a(n) = Sum_{m=1..n} A145357(n,m).

Extensions

Changed offset from 0 to 1 by Wolfdieter Lang, Nov 17 2008

A145360 Third column (m=3) of triangle A145357 (S1hat(6)).

Original entry on oeis.org

1, 6, 78, 804, 8316, 85176, 1021608, 11394432, 144885888, 1886008320, 26529503616, 390680672256, 6237490904064, 104348756736000, 1873079661358080, 35428981499412480, 710916534432276480, 14999585506406645760, 333292875250857984000, 7754472236069830656000
Offset: 0

Views

Author

Wolfdieter Lang, Oct 17 2008

Keywords

Crossrefs

Cf. A001725 (first column), A145359 (second column).

Formula

a(n) = A145357(n+3,3), n>=0.

A145356 Partition number array, called M31hat(6).

Original entry on oeis.org

1, 6, 1, 42, 6, 1, 336, 42, 36, 6, 1, 3024, 336, 252, 42, 36, 6, 1, 30240, 3024, 2016, 1764, 336, 252, 216, 42, 36, 6, 1, 332640, 30240, 18144, 14112, 3024, 2016, 1764, 1512, 336, 252, 216, 42, 36, 6, 1, 3991680, 332640, 181440, 127008, 112896, 30240, 18144, 14112
Offset: 1

Views

Author

Wolfdieter Lang, Oct 17 2008, Oct 28 2008

Keywords

Comments

Each partition of n, ordered like in Abramowitz-Stegun (A-St order; for the reference see A134278), is mapped to a nonnegative integer a(n,k) =: M31hat(6;n,k) with the k-th partition of n in A-St order.
The sequence of row lengths is A000041 (partition numbers) [1, 2, 3, 5, 7, 11, 15, 22, 30, 42,...].
Sixth member (K=6) in the family M31hat(K) of partition number arrays.
If M31hat(6;n,k) is summed over those k numerating partitions with fixed number of parts m one obtains the unsigned triangle S1hat(6):= A145357.

Examples

			Triangle begins
  [1];
  [6,1];
  [42,6,1];
  [336,42,36,6,1];
  [3024,336,252,42,36,6,1];
  ...
a(4,3)= 36 = |S1(6;2,1)|^2. The relevant partition of 4 is (2^2).
		

Crossrefs

Cf. A145358 (row sums).
Cf. A144890 (M31hat(5) array), A145357 (S1hat(6)).

Formula

a(n,k) = product(|S1(6;j,1)|^e(n,k,j),j=1..n) with |S1(6;n,1)| = A049374(n,1) = A001725(n+4) = [1,6,42,336,3024,30240,332640,...] = (n+4)!/5!, n>=1 and 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.
Showing 1-4 of 4 results.