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 1-6 of 6 results.

A104150 Shifted factorial numbers: a(0)=0, a(n) = (n-1)!.

Original entry on oeis.org

0, 1, 1, 2, 6, 24, 120, 720, 5040, 40320, 362880, 3628800, 39916800, 479001600, 6227020800, 87178291200, 1307674368000, 20922789888000, 355687428096000, 6402373705728000, 121645100408832000, 2432902008176640000, 51090942171709440000, 1124000727777607680000
Offset: 0

Views

Author

Miklos Kristof, Mar 08 2005

Keywords

Comments

E.g.f.: Sum_{n>=1} (n-1)!*x^n/n! = Sum_{n>=1} x^n/n.
The shift law of the e.g.f.: if Sum_{n>=0} a(n)*x^n/n! = f(x), then Sum_{n>=0} a(n+1)*x^n/n! = d/dx f(x) and Sum_{n>=1} a(n-1)*x^n/n! = Integral f(x) dx.
The e.g.f. of A000142 (= n!) is 1/(1-x), so the e.g.f. of a(n)=(n-1)! is integral 1/(1-x) = -log(1-x).

References

  • A. N. Khovanskii. The Application of Continued Fractions and Their Generalizations to Problem in Approximation Theory. Groningen: Noordhoff, Netherlands, 1963. See p.141 (10.19)

Crossrefs

Cf. A000142.
Column k=1 of A285849.
Main diagonal of A295027 (for n > 0).

Programs

  • Magma
    [0] cat [Factorial(n-1): n in [1..25]]; // Vincenzo Librandi, Dec 25 2012
    
  • Mathematica
    Join[{0,1},Range[20]!] (* Harvey P. Dale, Dec 09 2013 *)
  • PARI
    my(x='x+O('x^30)); concat([0], Vec(serlaplace(-log(1-x)))) \\ G. C. Greubel, May 15 2018
  • Sage
    [stirling_number1(n,1) for n in range(0, 22)] # Zerinvary Lajos, May 16 2009
    

Formula

E.g.f. -log(1-x) = x + x^2/2 + x^3/3 + ... + x^n/n + ...
G.f.: x+x^2/(G(0)-x) where G(k) = 1 - (k+1)*x/(1 - x*(k+2)/G(k+1)); G(0) = W(1,1;-x)/W(1,2;-x), W(a,b,x) = 1 - a*b*x/1! + a*(a+1)*b*(b+1)*x^2/2! - ... + a*(a+1)*...*(a+n-1)*b*(b+1)*...*(b+n-1)*x^n/n! + ...; see [A. N. Khovanskii, p. 141 (10.19)], x-> -x; (continued fraction, 2-step). - Sergei N. Gladkovskii, Aug 14 2012
E.g.f.: (-x + 5*x^2/2 - 11*x^3/6 + x^4/4 + x^5/(W(0)-x)/4)/(x-1)^3 where W(k)= (x + 1)*k + x + 5 - x*(k+2)*(k+5)/W(k+1); see [S. N. Gladkovskii, p. 79 (5.1.21)]; (continued fraction, Euler's 1st kind, 1-step). - Sergei N. Gladkovskii, Aug 15 2012
G.f.: A(x) = Integral_{t>=0} x*exp(-t)/(1-x*t) dt = x/G(0) where G(k) = 1 - x*(k+1)/(1 - x*(k+1)/G(k+1)); (continued fraction due to L. Euler and E. N. Laguerre). - Sergei N. Gladkovskii, Dec 24 2012
G.f.: x + x/Q(0), where Q(k)= 1/x - (2*k+2) - (k+2)*(k+1)/Q(k+1); (continued fraction). - Sergei N. Gladkovskii, Apr 25 2013
G.f.: x/Q(0), where Q(k) = 1 - x*(k+1)/(1 - x*(k+1)/Q(k+1)); (continued fraction). - Sergei N. Gladkovskii, May 20 2013
G.f.: x*G(0), where G(k) = 1 + x*(2*k+1)/(1 - x*(2*k+2)/(x*(2*k+2) + 1/G(k+1))); (continued fraction). - Sergei N. Gladkovskii, Jun 07 2013
G.f.: x*G(0), where G(k) = 1 - x*(k+1)/(x*(k+1) - 1/(1 - x*(k+1)/(x*(k+1) - 1/G(k+1) ))); (continued fraction). - Sergei N. Gladkovskii, Aug 07 2013

A295028 A(n,k) is (1/n) times the n-th derivative of the k-th tetration of x (power tower of order k) x^^k at x=1; square array A(n,k), n>=1, k>=1, read by antidiagonals.

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 3, 2, 0, 1, 1, 3, 8, 2, 0, 1, 1, 3, 14, 36, 9, 0, 1, 1, 3, 14, 72, 159, -6, 0, 1, 1, 3, 14, 96, 489, 932, 118, 0, 1, 1, 3, 14, 96, 729, 3722, 5627, -568, 0, 1, 1, 3, 14, 96, 849, 6842, 33641, 40016, 4716, 0
Offset: 1

Views

Author

Alois P. Heinz, Nov 12 2017

Keywords

Examples

			Square array A(n,k) begins:
  1,   1,    1,     1,     1,      1,      1,      1, ...
  0,   1,    1,     1,     1,      1,      1,      1, ...
  0,   1,    3,     3,     3,      3,      3,      3, ...
  0,   2,    8,    14,    14,     14,     14,     14, ...
  0,   2,   36,    72,    96,     96,     96,     96, ...
  0,   9,  159,   489,   729,    849,    849,    849, ...
  0,  -6,  932,  3722,  6842,   8642,   9362,   9362, ...
  0, 118, 5627, 33641, 71861, 102941, 118061, 123101, ...
		

Crossrefs

Main diagonal gives A136461(n-1).

Programs

  • Maple
    f:= proc(n) f(n):= `if`(n=0, 1, (x+1)^f(n-1)) end:
    A:= (n, k)-> (n-1)!*coeff(series(f(k), x, n+1), x, n):
    seq(seq(A(n, 1+d-n), n=1..d), d=1..14);
    # second Maple program:
    b:= proc(n, k) option remember; `if`(n=0, 1, `if`(k=0, 0,
          -add(binomial(n-1, j)*b(j, k)*add(binomial(n-j, i)*
          (-1)^i*b(n-j-i, k-1)*(i-1)!, i=1..n-j), j=0..n-1)))
        end:
    A:= (n, k)-> b(n, min(k, n))/n:
    seq(seq(A(n, 1+d-n), n=1..d), d=1..14);
  • Mathematica
    b[n_, k_] := b[n, k] = If[n == 0, 1, If[k == 0, 0, -Sum[Binomial[n - 1, j]*b[j, k]*Sum[Binomial[n - j, i]*(-1)^i*b[n - j - i, k - 1]*(i - 1)!, {i, 1, n - j}], {j, 0, n - 1}]]];
    A[n_, k_] := b[n, Min[k, n]]/n;
    Table[A[n, 1 + d - n], {d, 1, 14}, {n, 1, d}] // Flatten (* Jean-François Alcover, May 25 2018, translated from 2nd Maple program *)

Formula

A(n,k) = 1/n * [(d/dx)^n x^^k]_{x=1}.
A(n,k) = (n-1)! * [x^n] (x+1)^^k.
A(n,k) = Sum_{i=0..min(n,k)} A295027(n,i).
A(n,k) = 1/n * A277537(n,k).

A277536 T(n,k) is the n-th derivative of the difference between the k-th tetration of x (power tower of order k) and its predecessor (or 0 if k=0) at x=1; triangle T(n,k), n>=0, 0<=k<=n, read by rows.

Original entry on oeis.org

1, 0, 1, 0, 0, 2, 0, 0, 3, 6, 0, 0, 8, 24, 24, 0, 0, 10, 170, 180, 120, 0, 0, 54, 900, 1980, 1440, 720, 0, 0, -42, 6566, 19530, 21840, 12600, 5040, 0, 0, 944, 44072, 224112, 305760, 248640, 120960, 40320, 0, 0, -5112, 365256, 2650536, 4818744, 4536000, 2993760, 1270080, 362880
Offset: 0

Views

Author

Alois P. Heinz, Oct 19 2016

Keywords

Comments

T(n,k) is defined for all n,k >= 0. The triangle contains only the terms with k<=n. T(n,k) = 0 for k>n.

Examples

			Triangle T(n,k) begins:
  1;
  0, 1;
  0, 0,   2;
  0, 0,   3,     6;
  0, 0,   8,    24,     24;
  0, 0,  10,   170,    180,    120;
  0, 0,  54,   900,   1980,   1440,    720;
  0, 0, -42,  6566,  19530,  21840,  12600,   5040;
  0, 0, 944, 44072, 224112, 305760, 248640, 120960, 40320;
  ...
		

Crossrefs

Columns k=0-2 give: A000007, A063524, A005727 (for n>1).
Main diagonal gives A000142.
Row sums give A033917.
T(n+1,n)/3 gives A005990.
T(2n,n) gives A290023.

Programs

  • Maple
    f:= proc(n) option remember; `if`(n<0, 0,
          `if`(n=0, 1, (x+1)^f(n-1)))
        end:
    T:= (n, k)-> n!*coeff(series(f(k)-f(k-1), x, n+1), x, n):
    seq(seq(T(n, k), k=0..n), n=0..12);
    # second Maple program:
    b:= proc(n, k) option remember; `if`(n=0, 1, `if`(k=0, 0,
          -add(binomial(n-1, j)*b(j, k)*add(binomial(n-j, i)*
          (-1)^i*b(n-j-i, k-1)*(i-1)!, i=1..n-j), j=0..n-1)))
        end:
    T:= (n, k)-> b(n, min(k, n))-`if`(k=0, 0, b(n, min(k-1, n))):
    seq(seq(T(n, k), k=0..n), n=0..12);
  • Mathematica
    f[n_] := f[n] = If[n < 0, 0, If[n == 0, 1, (x + 1)^f[n - 1]]];
    T[n_, k_] := n!*SeriesCoefficient[f[k] - f[k - 1], { x, 0, n}];
    Table[T[n, k], {n, 0, 12}, {k, 0, n}] // Flatten
    (* second program: *)
    b[n_, k_] := b[n, k] = If[n == 0, 1, If[k == 0, 0, -Sum[Binomial[n - 1, j]*b[j, k]*Sum[Binomial[n - j, i]*(-1)^i*b[n - j - i, k - 1]*(i - 1)!, {i, 1, n - j}], {j, 0, n - 1}]]];
    T[n_, k_] := (b[n, Min[k, n]] - If[k == 0, 0, b[n, Min[k - 1, n]]]);
    Table[T[n, k], {n, 0, 12}, {k, 0, n}] // Flatten (* Jean-François Alcover, May 28 2018, from Maple *)

Formula

E.g.f. of column k>0: (x+1)^^k - (x+1)^^(k-1), e.g.f. of column k=0: 1.
T(n,k) = [(d/dx)^n (x^^k - x^^(k-1))]_{x=1} for k>0, T(n,0) = A000007(n).
T(n,k) = A277537(n,k) - A277537(n,k-1) for k>0, T(n,0) = A000007(n).
T(n,k) = n * A295027(n,k) for n,k > 0.

A005168 n-th derivative of x^x at 1, divided by n.

Original entry on oeis.org

1, 1, 1, 2, 2, 9, -6, 118, -568, 4716, -38160, 358126, -3662088, 41073096, -500013528, 6573808200, -92840971200, 1402148010528, -22554146644416, 385014881294496, -6952611764874240, 132427188835260480, -2653529921603890560, 55802195178451990896
Offset: 1

Views

Author

Keywords

References

  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Cf. A005727.
Column k=2 of A295027 (for n>1), A295028.

Programs

  • Maple
    a:= n-> (n-1)! *coeftayl(x^x, x=1, n):
    seq(a(n), n=1..30);  # Alois P. Heinz, Aug 18 2012
  • Mathematica
    Rest[(NestList[ Factor[ D[ #1, x]] &, x^x, 23] /. (x -> 1))/Range[0, 23]] (* Robert G. Wilson v, Aug 10 2010 *)
  • Python
    from sympy import var, diff
    x = var('x')
    y = x**x
    l = [[y:=diff(y),y.subs(x,1)/(n+1)][1] for n in range(10)]
    print(l) # Nicholas Stefan Georgescu, Mar 02 2023

Extensions

One more term from Robert G. Wilson v, Aug 10 2010

A136461 Expansion of e.g.f.: A(x) = -(1 + LambertW(-log(1+x))/log(1+x))/x.

Original entry on oeis.org

1, 1, 3, 14, 96, 849, 9362, 123101, 1888016, 33066768, 651883152, 14286514186, 344690210928, 9079702374300, 259327537407416, 7983107543564724, 263518937698466304, 9285770278110061664, 347916420499685643072, 13812127364516107258944, 579183295530010157485824
Offset: 0

Views

Author

Paul D. Hanna, Dec 31 2007

Keywords

Comments

A033917 gives the coefficients of iterated exponential function defined by y(x) = x^y(x) expanded about x=1.

Crossrefs

Cf. A033917.
Row sums of A295027 (shifted).
Main diagonal of A295028 (shifted).

Programs

  • Maple
    a:= n-> add(Stirling1(n+1, k)*(k+1)^(k-1), k=0..n+1)/(n+1):
    seq(a(n), n=0..25);  # Alois P. Heinz, Jan 21 2016
  • Mathematica
    CoefficientList[Series[-(1+LambertW[-Log[1+x]]/Log[1+x])/x, {x, 0, 20}], x]* Range[0, 20]! (* Vaclav Kotesovec, Nov 27 2012 *)
  • PARI
    {a(n)=n!*polcoeff(sum(i=0,n+1,(i+1)^(i-1)*log(1+x +O(x^(n+2) ))^i/i!), n+1)}
    
  • PARI
    x='x+O('x^30); Vec(serlaplace(-(1+lambertw(-log(1+x))/log(1+x))/x  )) \\ G. C. Greubel, Feb 19 2018

Formula

a(n) = A033917(n+1)/(n+1).
E.g.f.: A(x) = (1/x)*Sum_{i>=1} (i+1)^(i-1) * log(1+x)^i/i!.
a(n) ~ n^(n-1) / ( exp(n-3/2+exp(-1)/2) * (exp(exp(-1))-1)^(n+1/2) ). - Vaclav Kotesovec, Nov 27 2012

A298605 T(n,k) is 1/(k-1)! times the n-th derivative of the difference between the k-th tetration of x (power tower of order k) and its predecessor at x=1; triangle T(n,k), n>=1, 1<=k<=n, read by rows.

Original entry on oeis.org

1, 0, 2, 0, 3, 3, 0, 8, 12, 4, 0, 10, 85, 30, 5, 0, 54, 450, 330, 60, 6, 0, -42, 3283, 3255, 910, 105, 7, 0, 944, 22036, 37352, 12740, 2072, 168, 8, 0, -5112, 182628, 441756, 200781, 37800, 4158, 252, 9, 0, 47160, 1488240, 5765540, 3282300, 747390, 94500, 7620, 360, 10
Offset: 1

Views

Author

Alois P. Heinz, Jan 22 2018

Keywords

Examples

			Triangle T(n,k) begins:
  1;
  0,     2;
  0,     3,       3;
  0,     8,      12,       4;
  0,    10,      85,      30,       5;
  0,    54,     450,     330,      60,      6;
  0,   -42,    3283,    3255,     910,    105,     7;
  0,   944,   22036,   37352,   12740,   2072,   168,    8;
  0, -5112,  182628,  441756,  200781,  37800,  4158,  252,   9;
  0, 47160, 1488240, 5765540, 3282300, 747390, 94500, 7620, 360, 10;
  ...
		

Crossrefs

Columns k=1-2 give: A063524, A005727 (for n>1).
Main diagonal gives A000027.

Programs

  • Maple
    f:= proc(n) option remember; `if`(n<0, 0,
          `if`(n=0, 1, (x+1)^f(n-1)))
        end:
    T:= (n, k)-> n!/(k-1)!*coeff(series(f(k)-f(k-1), x, n+1), x, n):
    seq(seq(T(n, k), k=1..n), n=1..10);
    # second Maple program:
    b:= proc(n, k) option remember; `if`(n=0, 1, `if`(k=0, 0,
          -add(binomial(n-1, j)*b(j, k)*add(binomial(n-j, i)*
          (-1)^i*b(n-j-i, k-1)*(i-1)!, i=1..n-j), j=0..n-1)))
        end:
    T:= (n, k)-> (b(n, min(k, n))-`if`(k=0, 0, b(n, min(k-1, n))))/(k-1)!:
    seq(seq(T(n, k), k=1..n), n=1..10);
  • Mathematica
    f[n_] := f[n] = If[n < 0, 0, If[n == 0, 1, (x + 1)^f[n - 1]]];
    T[n_, k_] := n!/(k - 1)!*SeriesCoefficient[f[k] - f[k - 1], { x, 0, n}];
    Table[T[n, k], {n, 1, 10}, { k, 1, n}] // Flatten
    (* Second program: *)
    b[n_, k_] := b[n, k] = If[n == 0, 1, If[k == 0, 0, -Sum[Binomial[n-1, j]* b[j, k]*Sum[Binomial[n - j, i]* (-1)^i*b[n - j - i, k - 1]*(i - 1)!, {i, 1, n - j}], {j, 0, n - 1}]]];
    T[n_, k_] := (b[n, Min[k, n]] - If[k == 0, 0, b[n, Min[k-1, n]]])/(k-1)!;
    Table[T[n, k], {n, 1, 10}, { k, 1, n}] // Flatten (* Jean-François Alcover, Jun 03 2018, from Maple *)

Formula

T(n,k) = n!/(k-1)! * [x^n] ((x+1)^^k - (x+1)^^(k-1)).
T(n,k) = 1/(k-1)! * [(d/dx)^n (x^^k - x^^(k-1))]_{x=1}.
T(n,k) = 1/(k-1)! * A277536(n,k).
T(n,k) = n/(k-1)! * A295027(n,k).
Showing 1-6 of 6 results.