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 1-4 of 4 results.

A351429 Square array T(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of e.g.f. 1/(1 + f^k(x)), where f(x) = exp(x) - 1.

Original entry on oeis.org

1, 1, -1, 1, -1, 2, 1, -1, 1, -6, 1, -1, 0, -1, 24, 1, -1, -1, 1, 1, -120, 1, -1, -2, 0, 1, -1, 720, 1, -1, -3, -4, 6, -2, 1, -5040, 1, -1, -4, -11, -2, 32, -9, -1, 40320, 1, -1, -5, -21, -41, 76, 115, -9, 1, -362880, 1, -1, -6, -34, -129, -75, 953, 172, 50, -1, 3628800
Offset: 0

Views

Author

Seiichi Manyama, Feb 11 2022

Keywords

Examples

			Square array begins:
     1,  1,  1,   1,   1,    1,     1, ...
    -1, -1, -1,  -1,  -1,   -1,    -1, ...
     2,  1,  0,  -1,  -2,   -3,    -4, ...
    -6, -1,  1,   0,  -4,  -11,   -21, ...
    24,  1,  1,   6,  -2,  -41,  -129, ...
  -120, -1, -2,  32,  76,  -75,  -806, ...
   720,  1, -9, 115, 953, 1540, -3334, ...
		

Crossrefs

Columns k=0..5 give A133942, A033999, A000587, A130410, A351427, A351428.
Main diagonal gives A351433.

Programs

  • Maple
    A:= (n, k)-> n!*(g->coeff(series(1/(1+(g@@k)(x)), x, n+1), x, n))(x->exp(x)-1):
    seq(seq(A(n, d-n), n=0..d), d=0..10);  # Alois P. Heinz, Feb 11 2022
  • Mathematica
    T[n_, 0] := (-1)^n*n!; T[n_, k_] := T[n, k] = Sum[StirlingS2[n, j]*T[j, k - 1], {j, 0, n}]; Table[T[k, n - k], {n, 0, 10}, {k, 0, n}] // Flatten (* Amiram Eldar, Feb 11 2022 *)
  • PARI
    T(n, k) = if(k==0, (-1)^n*n!, sum(j=0, n, stirling(n, j, 2)*T(j, k-1)));

Formula

T(n,k) = Sum_{j=0..n} Stirling2(n,j) * T(j,k-1), k>1, T(n,0) = (-1)^n * n!.

A351428 Expansion of e.g.f. 1/exp(exp(exp(exp(exp(x)-1)-1)-1)-1).

Original entry on oeis.org

1, -1, -3, -11, -41, -75, 1540, 37725, 657715, 10551750, 163089430, 2407275470, 31865298262, 290682880132, -2479867505029, -267542605513289, -11438897571729494, -404343336811199242, -13192591498632627584, -410340915410006575406, -12233989907129223814578
Offset: 0

Views

Author

Seiichi Manyama, Feb 11 2022

Keywords

Crossrefs

Column k=5 of A351429.

Programs

  • Maple
    g:= x-> exp(x)-1:
    a:= n-> n! * coeff(series(1/((g@@5)(x)+1), x, n+1), x, n):
    seq(a(n), n=0..20);  # Alois P. Heinz, Feb 11 2022
  • Mathematica
    T[n_, 0] := (-1)^n * n!; T[n_, k_] := T[n, k] = Sum[StirlingS2[n, j]*T[j, k - 1], {j, 0, n}]; a[n_] := T[n, 5]; Array[a, 20, 0] (* Amiram Eldar, Feb 11 2022 *)
    With[{nn=20},CoefficientList[Series[1/Exp[Exp[Exp[Exp[Exp[x]-1]-1]-1]-1],{x,0,nn}],x] Range[0,nn]!] (* Harvey P. Dale, Feb 09 2025 *)
  • PARI
    my(N=40, x='x+O('x^N)); Vec(serlaplace(1/exp(exp(exp(exp(exp(x)-1)-1)-1)-1)))
    
  • PARI
    T(n, k) = if(k==0, (-1)^n*n!, sum(j=0, n, stirling(n, j, 2)*T(j, k-1)));
    a(n) = T(n, 5);

Formula

a(n) = T(n,5), T(n,k) = Sum_{j=0..n} Stirling2(n,j) * T(j,k-1), k>1, T(n,0) = (-1)^n * n!.

A363008 Expansion of e.g.f. 1/(2 - exp(exp(exp(exp(x) - 1) - 1) - 1)).

Original entry on oeis.org

1, 1, 6, 52, 594, 8444, 143783, 2854261, 64735570, 1651560175, 46814933977, 1459689346911, 49650414218071, 1829560770160335, 72603137881845927, 3086932915850946633, 139999909097319319787, 6746170002325663539844, 344199636595620793896784
Offset: 0

Views

Author

Seiichi Manyama, May 12 2023

Keywords

Crossrefs

Row p=4 of A153278 (for n>=1).
Column k=4 of A363007.
Cf. A351427.

Programs

  • Maple
    b:= proc(n, m, t) option remember; `if`(n=0, `if`(t=1, m!,
          b(m, 0, t-1)), m*b(n-1, m, t)+b(n-1, m+1, t))
        end:
    a:= n-> b(n, 0, 4):
    seq(a(n), n=0..20);  # Alois P. Heinz, May 12 2023
  • PARI
    my(N=20, x='x+O('x^N)); Vec(serlaplace(1/(2-exp(exp(exp(exp(x)-1)-1)-1))))

Formula

a(n) = T(n,4), T(n,k) = Sum_{j=0..n} Stirling2(n,j) * T(j,k-1), k>1, T(n,0) = n!.

A351422 Expansion of e.g.f. -log(1 - log(1 + log(1 + log(1+x)))).

Original entry on oeis.org

1, -2, 8, -48, 386, -3905, 47701, -683592, 11250291, -209168071, 4336482905, -99197868847, 2481962140797, -67426166949102, 1976463051528507, -62178381389729317, 2089532143617395264, -74702625442877063902, 2830904065389397804534, -113348477836878447492630
Offset: 1

Views

Author

Seiichi Manyama, Feb 11 2022

Keywords

Crossrefs

Column k=4 of A351420.

Programs

  • Mathematica
    T[n_, 1] := (n - 1)!; T[n_, k_] := T[n, k] = Sum[StirlingS1[n, j] * T[j, k - 1], {j, 1, n}]; a[n_] := T[n, 4]; Array[a, 20] (* Amiram Eldar, Feb 11 2022 *)
  • PARI
    my(N=40, x='x+O('x^N)); Vec(serlaplace(-log(1-log(1+log(1+log(1+x))))))
    
  • PARI
    T(n, k) = if(k==1, (n-1)!, sum(j=1, n, stirling(n, j, 1)*T(j, k-1)));
    a(n) = T(n, 4);

Formula

a(n) = T(n,4), T(n,k) = Sum_{j=1..n} Stirling1(n,j) * T(j,k-1), k>1, T(n,1) = (n-1)!.
Showing 1-4 of 4 results.