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 1-10 of 12 results. Next

A277537 A(n,k) is 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>=0, k>=0, read by antidiagonals.

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 1, 0, 0, 1, 1, 2, 0, 0, 1, 1, 2, 3, 0, 0, 1, 1, 2, 9, 8, 0, 0, 1, 1, 2, 9, 32, 10, 0, 0, 1, 1, 2, 9, 56, 180, 54, 0, 0, 1, 1, 2, 9, 56, 360, 954, -42, 0, 0, 1, 1, 2, 9, 56, 480, 2934, 6524, 944, 0, 0, 1, 1, 2, 9, 56, 480, 4374, 26054, 45016, -5112, 0, 0
Offset: 0

Views

Author

Alois P. Heinz, Oct 19 2016

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, 0,   2,    2,     2,     2,     2,     2, ...
  0, 0,   3,    9,     9,     9,     9,     9, ...
  0, 0,   8,   32,    56,    56,    56,    56, ...
  0, 0,  10,  180,   360,   480,   480,   480, ...
  0, 0,  54,  954,  2934,  4374,  5094,  5094, ...
  0, 0, -42, 6524, 26054, 47894, 60494, 65534, ...
		

Crossrefs

Rows n=0..1 give A000012, A057427.
Main diagonal gives A033917.

Programs

  • Maple
    f:= proc(n) f(n):= `if`(n=0, 1, (x+1)^f(n-1)) end:
    A:= (n, k)-> n!*coeff(series(f(k), x, n+1), x, n):
    seq(seq(A(n, d-n), n=0..d), d=0..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)):
    seq(seq(A(n, d-n), n=0..d), d=0..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]]; Table[A[n, d-n], {d, 0, 14}, {n, 0, d}] // Flatten (* Jean-François Alcover, Jan 14 2017, adapted from 2nd Maple prog. *)

Formula

A(n,k) = [(d/dx)^n x^^k]_{x=1}.
E.g.f. of column k: (x+1)^^k.
A(n,k) = Sum_{i=0..min(n,k)} A277536(n,i).
A(n,k) = n * A295028(n,k) for n,k > 0.

A295027 T(n,k) is (1/n) 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, 1, 0, 1, 2, 0, 2, 6, 6, 0, 2, 34, 36, 24, 0, 9, 150, 330, 240, 120, 0, -6, 938, 2790, 3120, 1800, 720, 0, 118, 5509, 28014, 38220, 31080, 15120, 5040, 0, -568, 40584, 294504, 535416, 504000, 332640, 141120, 40320, 0, 4716, 297648, 3459324, 7877520, 8968680, 6804000, 3840480, 1451520, 362880
Offset: 1

Views

Author

Alois P. Heinz, Nov 12 2017

Keywords

Comments

T(n,k) is defined for all n,k >= 1. 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,    1,     2;
  0,    2,     6,      6;
  0,    2,    34,     36,     24;
  0,    9,   150,    330,    240,    120;
  0,   -6,   938,   2790,   3120,   1800,    720;
  0,  118,  5509,  28014,  38220,  31080,  15120,   5040;
  0, -568, 40584, 294504, 535416, 504000, 332640, 141120, 40320;
  ...
		

Crossrefs

Column k=2 gives A005168 for n>1.
Row sums give A136461(n-1).
Main diagonal gives A104150 (for n>0).

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-1)!*coeff(series(f(k)-f(k-1), x, n+1), x, n):
    seq(seq(T(n, k), k=1..n), n=1..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))))/n:
    seq(seq(T(n, k), k=1..n), n=1..12);
  • Mathematica
    f[n_] := f[n] = If[n < 0, 0, If[n == 0, 1, (x + 1)^f[n - 1]]];
    T[n_, k_] := (n - 1)!*SeriesCoefficient[f[k] - f[k - 1], {x, 0, n}];
    Table[T[n, k], {n, 1, 12}, {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]]])/n;
    Table[T[n, k], {n, 1, 12}, {k, 1, n}] // Flatten (* Jean-François Alcover, May 28 2018, from Maple *)

Formula

T(n,k) = (n-1)! * [x^n] ((x+1)^^k - (x+1)^^(k-1)).
T(n,k) = 1/n * [(d/dx)^n (x^^k - x^^(k-1))]_{x=1}.
T(n,k) = A295028(n,k) - A295028(n,k-1).
T(n,k) = 1/n * A277536(n,k).
T(n+1,n) = A001286(n).

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

A295103 a(n) = (1/n) times the n-th derivative of the third tetration of x (power tower of order 3) x^^3 at x=1.

Original entry on oeis.org

1, 1, 3, 8, 36, 159, 932, 5627, 40016, 302364, 2510712, 22623490, 213486864, 2227719948, 23388469400, 277570328040, 3182959484736, 42530335589088, 523078873327872, 7846745537655360, 101370634558327680, 1717052148685665792, 22657314273376353408
Offset: 1

Views

Author

Alois P. Heinz, Nov 14 2017

Keywords

Comments

First term < 0: a(33) = -26329560314038014690778779463680.

Crossrefs

Column k=3 of A295028.
Cf. A179230.

Programs

  • Maple
    f:= proc(n) f(n):= `if`(n=0, 1, (x+1)^f(n-1)) end:
    a:= n-> (n-1)!*coeff(series(f(3), x, n+1), x, n):
    seq(a(n), n=1..23);
  • Mathematica
    f[n_] := f[n] = If[n == 0, 1, (x + 1)^f[n - 1]];
    a[n_] := (n - 1)!*SeriesCoefficient[f[3], {x, 0, n}];
    Array[a, 23] (* Jean-François Alcover, May 31 2018, from Maple *)

Formula

a(n) = 1/n * [(d/dx)^n x^^3]_{x=1}.
a(n) = (n-1)! * [x^n] (x+1)^^3.
a(n) = 1/n * A179230(n).

A295104 a(n) = (1/n) times the n-th derivative of the fourth tetration of x (power tower of order 4) x^^4 at x=1.

Original entry on oeis.org

1, 1, 3, 14, 72, 489, 3722, 33641, 334520, 3761688, 45898272, 615641806, 8863726704, 137786878644, 2279658872696, 40229212948404, 750433323448128, 14801457167223872, 306869893647304896, 6683254543551623904, 152281219079726183040, 3626445842114839589952
Offset: 1

Views

Author

Alois P. Heinz, Nov 14 2017

Keywords

Comments

First term < 0: a(329).

Crossrefs

Column k=4 of A295028.
Cf. A179405.

Programs

  • Maple
    f:= proc(n) f(n):= `if`(n=0, 1, (x+1)^f(n-1)) end:
    a:= n-> (n-1)!*coeff(series(f(4), x, n+1), x, n):
    seq(a(n), n=1..23);
  • Mathematica
    f[n_] := f[n] = If[n == 0, 1, (x + 1)^f[n - 1]];
    a[n_] := (n - 1)!*SeriesCoefficient[f[4], {x, 0, n}];
    Array[a, 23] (* Jean-François Alcover, May 31 2018, from Maple *)

Formula

a(n) = 1/n * [(d/dx)^n x^^4]_{x=1}.
a(n) = (n-1)! * [x^n] (x+1)^^4.
a(n) = 1/n * A179405(n).

A295105 a(n) = (1/n) times the n-th derivative of the fifth tetration of x (power tower of order 5) x^^5 at x=1.

Original entry on oeis.org

1, 1, 3, 14, 96, 729, 6842, 71861, 869936, 11639208, 172823592, 2797075786, 49197117648, 931938081060, 18931744650296, 410210251648404, 9443418462484224, 230108297407058144, 5915598580747789632, 159987606074180375904, 4539874767394840811904
Offset: 1

Views

Author

Alois P. Heinz, Nov 14 2017

Keywords

Crossrefs

Column k=5 of A295028.
Cf. A179505.

Programs

  • Maple
    f:= proc(n) f(n):= `if`(n=0, 1, (x+1)^f(n-1)) end:
    a:= n-> (n-1)!*coeff(series(f(5), x, n+1), x, n):
    seq(a(n), n=1..23);
  • Mathematica
    f[n_] := f[n] = If[n == 0, 1, (x + 1)^f[n - 1]];
    a[n_] := (n - 1)!*SeriesCoefficient[f[5], {x, 0, n}];
    Array[a, 23] (* Jean-François Alcover, May 31 2018, from Maple *)

Formula

a(n) = 1/n * [(d/dx)^n x^^5]_{x=1}.
a(n) = (n-1)! * [x^n] (x+1)^^5.
a(n) = 1/n * A179505(n).

A295106 a(n) = (1/n) times the n-th derivative of the sixth tetration of x (power tower of order 6) x^^6 at x=1.

Original entry on oeis.org

1, 1, 3, 14, 96, 849, 8642, 102941, 1373936, 20607888, 340516992, 6173590906, 121502258688, 2583247609500, 58940269686776, 1437019737587004, 37267502536335744, 1024420897710717344, 29745405670928179392, 909702365350759274304, 29224500667382460549504
Offset: 1

Views

Author

Alois P. Heinz, Nov 14 2017

Keywords

Crossrefs

Column k=6 of A295028.
Cf. A211205.

Programs

  • Maple
    f:= proc(n) f(n):= `if`(n=0, 1, (x+1)^f(n-1)) end:
    a:= n-> (n-1)!*coeff(series(f(6), x, n+1), x, n):
    seq(a(n), n=1..23);
  • Mathematica
    f[n_] := f[n] = If[n == 0, 1, (x + 1)^f[n - 1]];
    a[n_] := (n - 1)!*SeriesCoefficient[f[6], {x, 0, n}];
    Array[a, 23] (* Jean-François Alcover, May 31 2018, from Maple *)

Formula

a(n) = 1/n * [(d/dx)^n x^^6]_{x=1}.
a(n) = (n-1)! * [x^n] (x+1)^^6.
a(n) = 1/n * A211205(n).

A295107 a(n) = (1/n) times the n-th derivative of the seventh tetration of x (power tower of order 7) x^^7 at x=1.

Original entry on oeis.org

1, 1, 3, 14, 96, 849, 9362, 118061, 1706576, 27411888, 488133552, 9504647866, 201394553808, 4607546125740, 113271179680136, 2976610819616004, 83276079152315904, 2470817772641667104, 77492234876034762432, 2561350116102926727744, 88984716683633511515904
Offset: 1

Views

Author

Alois P. Heinz, Nov 14 2017

Keywords

Crossrefs

Column k=7 of A295028.
Cf. A277538.

Programs

  • Maple
    f:= proc(n) f(n):= `if`(n=0, 1, (x+1)^f(n-1)) end:
    a:= n-> (n-1)!*coeff(series(f(7), x, n+1), x, n):
    seq(a(n), n=1..23);
  • Mathematica
    f[n_] := f[n] = If[n == 0, 1, (x + 1)^f[n - 1]];
    a[n_] := (n - 1)!*SeriesCoefficient[f[7], {x, 0, n}];
    Array[a, 23] (* Jean-François Alcover, May 31 2018, from Maple *)

Formula

a(n) = 1/n * [(d/dx)^n x^^7]_{x=1}.
a(n) = (n-1)! * [x^n] (x+1)^^7.
a(n) = 1/n * A277538(n).

A295108 a(n) = (1/n) times the n-th derivative of the eighth tetration of x (power tower of order 8) x^^8 at x=1.

Original entry on oeis.org

1, 1, 3, 14, 96, 849, 9362, 123101, 1847696, 31252368, 584145552, 11981318986, 267050704368, 6432872588700, 166461202886456, 4606491806670324, 135733988375074944, 4243153626928512224, 140252989224067186752, 4887395830953148166784, 179067423776388634331904
Offset: 1

Views

Author

Alois P. Heinz, Nov 14 2017

Keywords

Crossrefs

Column k=8 of A295028.
Cf. A277539.

Programs

  • Maple
    f:= proc(n) f(n):= `if`(n=0, 1, (x+1)^f(n-1)) end:
    a:= n-> (n-1)!*coeff(series(f(8), x, n+1), x, n):
    seq(a(n), n=1..23);
  • Mathematica
    f[n_] := f[n] = If[n == 0, 1, (x + 1)^f[n - 1]];
    a[n_] := (n - 1)!*SeriesCoefficient[f[8], {x, 0, n}];
    Array[a, 23] (* Jean-François Alcover, May 31 2018, from Maple *)

Formula

a(n) = 1/n * [(d/dx)^n x^^8]_{x=1}.
a(n) = (n-1)! * [x^n] (x+1)^^8.
a(n) = 1/n * A277539(n).
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