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.

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A005727 n-th derivative of x^x at x=1. Also called Lehmer-Comtet numbers.

Original entry on oeis.org

1, 1, 2, 3, 8, 10, 54, -42, 944, -5112, 47160, -419760, 4297512, -47607144, 575023344, -7500202920, 105180931200, -1578296510400, 25238664189504, -428528786243904, 7700297625889920, -146004847062359040, 2913398154375730560, -61031188196889482880
Offset: 0

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Keywords

References

  • L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 139, table at foot of page.
  • G. H. Hardy, A Course of Pure Mathematics, 10th ed., Cambridge University Press, 1960, p. 428.
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Row sums of A008296. Column k=2 of A215703 and of A277537.

Programs

  • Maple
    A005727 := proc(n) option remember; `if`(n=0, 1, A005727(n-1)+add((-1)^(n-k)*(n-2-k)!*binomial(n-1, k)*A005727(k), k=0..n-2)) end:
    seq(A005727(n), n=0..23); # Mélika Tebni, May 22 2022
  • Mathematica
    NestList[ Factor[ D[ #1, x ] ]&, x^x, n ] /. (x->1)
    Range[0, 22]! CoefficientList[ Series[(1 + x)^(1 + x), {x, 0, 22}], x] (* Robert G. Wilson v, Feb 03 2013 *)
  • PARI
    a(n)=if(n<0,0,n!*polcoeff((1+x+x*O(x^n))^(1+x),n))

Formula

For n>0, a(n) = Sum_{k=0..n} b(n, k), where b(n, k) is a Lehmer-Comtet number of the first kind (see A008296).
E.g.f.: (1+x)^(1+x). a(n) = Sum_{k=0..n} Stirling1(n, k)*A000248(k). - Vladeta Jovovic, Oct 02 2003
From Mélika Tebni, May 22 2022: (Start)
a(0) = 1, a(n) = a(n-1)+Sum_{k=0..n-2} (-1)^(n-k)*(n-2-k)!*binomial(n-1, k)*a(k).
a(n) = Sum_{k=0..n} (-1)^(n-k)*A293297(k)*binomial(n, k).
a(n) = Sum_{k=0..n} (-1)^k*A203852(k)*binomial(n, k). (End)

A293472 Triangle read by rows, coefficients of polynomials in t = log(x) of the n-th derivative of x^x, evaluated at x = 1. T(n, k) with n >= 0 and 0 <= k <= n.

Original entry on oeis.org

1, 1, 1, 2, 2, 1, 3, 6, 3, 1, 8, 12, 12, 4, 1, 10, 40, 30, 20, 5, 1, 54, 60, 120, 60, 30, 6, 1, -42, 378, 210, 280, 105, 42, 7, 1, 944, -336, 1512, 560, 560, 168, 56, 8, 1, -5112, 8496, -1512, 4536, 1260, 1008, 252, 72, 9, 1
Offset: 0

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Author

Peter Luschny, Oct 10 2017

Keywords

Examples

			Triangle starts:
0: [  1]
1: [  1,   1]
2: [  2,   2,   1]
3: [  3,   6,   3,   1]
4: [  8,  12,  12,   4,   1]
5: [ 10,  40,  30,  20,   5,  1]
6: [ 54,  60, 120,  60,  30,  6, 1]
7: [-42, 378, 210, 280, 105, 42, 7, 1]
...
For n = 3, the 3rd derivative of x^x is p(3,x,t) = x^x*t^3 + 3*x^x*t^2 + 3*x^x*t + x^x + 3*x^x*t/x + 3*x^x/x - x^x/x^2 where log(x) is substituted by t. Evaluated at x = 1: p(3,1,t) = 3 + 6*t + 3*t^2 + t^3 with coefficients [3, 6, 3, 1].
		

Crossrefs

More generally, consider the n-th derivative of x^(x^m). This is case m = 1.
m | t = -1 | t = 0 | t = 1 | p(n, t) | related
m = 2 | - | A215524 | - | A293473 | A290268
m = 3 | - | A215704 | - | A293474 | -
Cf. A215703.

Programs

  • Maple
    dx := proc(m, n) if n = 0 then return [1] fi;
    subs(ln(x) = t, diff(x^(x^m), x$n)): subs(x = 1, %):
    PolynomialTools:-CoefficientList(%,t) end:
    ListTools:-Flatten([seq(dx(1, n), n=0..10)]);
  • Mathematica
    dx[m_, n_] := ReplaceAll[CoefficientList[ReplaceAll[Expand[D[x^x^m, {x, n}]], Log[x] -> t], t], x -> 1];
    Table[dx[1, n], {n, 0, 7}] // Flatten
Showing 1-2 of 2 results.