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.

A036073 Triangle of coefficients arising in calculation of A002872 and A002874 (sorting numbers).

Original entry on oeis.org

1, 2, 1, 5, 1, 6, 15, 1, 11, 30, 52, 1, 20, 80, 150, 203, 1, 37, 210, 525, 780, 877, 1, 70, 560, 1785, 3395, 4263, 4140, 1, 135, 1526, 6125, 14140, 22288, 24556, 21147, 1, 264, 4240, 21420, 58842, 109998, 150402, 149040, 115975, 1, 521, 11970, 76385, 248115
Offset: 0

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Author

Keywords

Comments

For connection to A002872, A002874, and other columns of A162663, see the formula in A162663. - Andrey Zabolotskiy, Oct 25 2017

Examples

			Triangle begins:
  1;
  .  2;
  .  1,  5;
  .  1,  6,  15;
  .  1, 11,  30,  52;
  .  1, 20,  80, 150, 203;
  .  1, 37, 210, 525, 780, 877;
  ...
		

References

  • T. S. Motzkin, Sorting numbers for cylinders and other classification numbers, in Combinatorics, Proc. Symp. Pure Math. 19, AMS, 1971, pp. 167-176.

Crossrefs

Row sums give A001861.
Diagonal gives A000110(n+1) - Alois P. Heinz, Mar 27 2013
Cf. A162663.

Programs

  • Maple
    egf:= exp(exp(x*y)+y*(exp(x)-1)-1):
    T:= (n, k)-> n!*coeff(series(coeff(series(egf, y, k+1)
                    , y, k), x, n+1), x, n):
    seq(seq(T(n, k), k=min(n, 1)..n), n=0..10);  # Alois P. Heinz, Mar 28 2013
  • PARI
    T(n, k) = { my(y = 'y + 'y*O('y^k), x = 'x + 'x*O('x^n); ); n!*polcoeff(polcoeff(exp(exp(x*y)+y*(exp(x)-1)-1), n, 'x), k, 'y); }
    for(n=0,10,for(k=0,n,print1(T(n,k),", "));print()); /* print triangle */
    \\ Michel Marcus, Mar 27 2013
    
  • PARI
    listpols(n)= {my(z = t + t*O(t^n)); zp = exp(exp(z)-1+(exp(p*z)-1)/p); for (i=0, n, print(i!*polcoeff(zp, i, t)););} \\ Michel Marcus, Mar 27 2013

Formula

E.g.f.: exp(exp(x*y)+y*(exp(x)-1)-1).

Extensions

Edited by Vladeta Jovovic, Sep 17 2003
Name corrected by Andrey Zabolotskiy, Oct 22 2017