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 1-2 of 2 results.

A369018 Triangle read by rows: T(n, k) = binomial(n, k - 1)*(k - 1)^(k - 1)*n*(n - k + 1)^(n - k).

Original entry on oeis.org

0, 0, 1, 0, 4, 4, 0, 27, 18, 36, 0, 256, 144, 192, 432, 0, 3125, 1600, 1800, 2700, 6400, 0, 46656, 22500, 23040, 29160, 46080, 112500, 0, 823543, 381024, 367500, 423360, 564480, 918750, 2286144, 0, 16777216, 7529536, 6967296, 7560000, 9175040, 12600000, 20901888, 52706752
Offset: 0

Views

Author

Peter Luschny, Jan 13 2024

Keywords

Examples

			Triangle read by rows:
[0] [0]
[1] [0,      1]
[2] [0,      4,      4]
[3] [0,     27,     18,     36]
[4] [0,    256,    144,    192,    432]
[5] [0,   3125,   1600,   1800,   2700,   6400]
[6] [0,  46656,  22500,  23040,  29160,  46080, 112500]
[7] [0, 823543, 381024, 367500, 423360, 564480, 918750, 2286144]
		

Crossrefs

Programs

  • Maple
    T := (n, k) -> binomial(n, k - 1)*(k - 1)^(k - 1)*n*(n - k + 1)^(n - k):
    seq(seq(T(n, k), k = 0..n), n=0..9);
  • Mathematica
    A369018[n_, k_] := Binomial[n, k-1] If[k == 1, 1, (k-1)^(k-1)] n (n-k+1)^(n-k);
    Table[A369018[n, k], {n, 0, 10}, {k, 0, n}] (* Paolo Xausa, Jan 27 2024 *)
  • SageMath
    def A369018(n, k):
        return binomial(n, k - 1)*(k - 1)^(k - 1)*n*(n - k + 1)^(n - k)

Formula

A369071 a(n) = Sum_{k=0..n} binomial(n, k - 1)*(k - 1)^(k - 1)*k*(n - k + 1)^(n - k).

Original entry on oeis.org

0, 1, 6, 57, 712, 10905, 197136, 4102777, 96552576, 2534382513, 73397843200, 2324613341721, 79923267523584, 2964436169152393, 117986961509824512, 5015721009078977625, 226816401312675168256, 10871698383944129824353, 550571805478900954497024
Offset: 0

Views

Author

Peter Luschny, Jan 13 2024

Keywords

Crossrefs

Cf. Row sums of A369019.

Programs

  • Maple
    A369071 := n -> local k; add(binomial(n, k-1)*(k-1)^(k-1)*k*(n-k+1)^(n-k), k=0..n): seq(A369071(n), n = 0..18);
  • Mathematica
    A369071[n_] := Sum[Binomial[n, k-1] If[k == 1, 1, (k-1)^(k-1)] k (n-k+1)^(n-k), {k, n}]; Array[A369071, 20, 0] (* Paolo Xausa, Jan 28 2024 *)
  • SageMath
    def A369071(n):
        return sum(binomial(n, k - 1)*(k - 1)^(k - 1)*k*(n - k + 1)^(n - k)
               for k in range(n + 1))
    print([A369071(n) for n in range(11)])
Showing 1-2 of 2 results.