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.

A155162 Triangle T(n,k) = binomial(n, k)*(k! + (n-k)!), read by rows.

Original entry on oeis.org

2, 2, 2, 3, 4, 3, 7, 9, 9, 7, 25, 28, 24, 28, 25, 121, 125, 80, 80, 125, 121, 721, 726, 390, 240, 390, 726, 721, 5041, 5047, 2562, 1050, 1050, 2562, 5047, 5041, 40321, 40328, 20216, 7056, 3360, 7056, 20216, 40328, 40321, 362881, 362889, 181512, 60984, 18144, 18144, 60984, 181512, 362889, 362881
Offset: 0

Views

Author

Roger L. Bagula, Jan 21 2009

Keywords

Examples

			Triangle begins as:
       2;
       2,      2;
       3,      4,      3;
       7,      9,      9,     7;
      25,     28,     24,    28,    25;
     121,    125,     80,    80,   125,   121;
     721,    726,    390,   240,   390,   726,   721;
    5041,   5047,   2562,  1050,  1050,  2562,  5047,   5041;
   40321,  40328,  20216,  7056,  3360,  7056, 20216,  40328,  40321;
  362881, 362889, 181512, 60984, 18144, 18144, 60984, 181512, 362889, 362881;
		

Crossrefs

Programs

  • Magma
    [Binomial(n,k)*(Factorial(k) + Factorial(n-k)): k in [0..n], n in [0..12]]; // G. C. Greubel, Mar 19 2021
    
  • Maple
    A155162:= (n,k)-> binomial(n,k)*(k! + (n-k)!); seq(seq(A155162(n,k), k=0..n), n=0..12); # G. C. Greubel, Mar 19 2021
  • Mathematica
    Table[Binomial[n,k](k! +(n-k)!), {n,0,12},{k,0,n}]//Flatten
  • Sage
    flatten([[binomial(n,k)*(factorial(k) + factorial(n-k)) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Mar 19 2021

Formula

T(n,k) = binomial(n, k)*(k! + (n-k)!).
Sum_{k=0..n} T(n, k) = 2*A000522(n) = A054091(n+1). - G. C. Greubel, Mar 19 2021

Extensions

Edited by G. C. Greubel, Mar 19 2021