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.

A076482 Triangle with T(n,k)=n!*(k-1)^k/k! where 1<=k<=n.

Original entry on oeis.org

0, 0, 1, 0, 3, 8, 0, 12, 32, 81, 0, 60, 160, 405, 1024, 0, 360, 960, 2430, 6144, 15625, 0, 2520, 6720, 17010, 43008, 109375, 279936, 0, 20160, 53760, 136080, 344064, 875000, 2239488, 5764801, 0, 181440, 483840, 1224720, 3096576, 7875000, 20155392, 51883209, 134217728
Offset: 1

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Author

Henry Bottomley, Oct 14 2002

Keywords

Examples

			Rows start
  0;
  0,   1;
  0,   3,   8;
  0,  12,  32,   81;
  0,  60, 160,  405, 1024;
  0, 360, 960, 2430, 6144, 15625;
  ...
		

Crossrefs

Row sums are A076483.

Programs

  • Mathematica
    Table[n! (k-1)^k/k!,{n,0,10},{k,n}]//Flatten (* Harvey P. Dale, Nov 28 2019 *)

Formula

T(n,k) = n*T(n, k-1) = A007778(k-1)*A008279(n,n-k) starting with T(n,n) = (n-1)^n = A007778(n-1).

A076630 a(n) is the smallest number such that product of first n terms is strictly greater than n-th power of a(n-1) starting with a(1)=1.

Original entry on oeis.org

1, 2, 5, 63, 1575297, 15398261127422599513389116979
Offset: 1

Views

Author

Henry Bottomley, Oct 22 2002

Keywords

Comments

Next term is 1.343...*10^160. Of the n^n ways of selecting n terms from {a(1),a(2),...,a(n)}, n!*Sum_k{1<=k<=n}(k-1)^k/k!=A076483(n) ways have a product strictly less than a(1)*a(2)*...*a(n) and this is possibly the smallest sequence with that property. If the definition had been: a(n) is the smallest number such that sum of first n terms is greater than n times a(n-1) starting with a(1)=1, then the resulting sequence would have been A003422.

Examples

			a(4)=1+floor[5^4/(1*2*5)]=1+floor[62.5]=63.
		

Crossrefs

Cf. A076483.

Formula

a(n) = 1 + floor[a(n-1)^n / Product_i{0
Showing 1-2 of 2 results.