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.

A003659 Shifts left under Stirling2 transform.

Original entry on oeis.org

1, 1, 2, 6, 26, 152, 1144, 10742, 122772, 1673856, 26780972, 496090330, 10519217930, 252851833482, 6832018188414, 205985750827854, 6885220780488694, 253685194149119818, 10250343686634687424, 452108221967363310278, 21676762640915055856716
Offset: 1

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Author

Keywords

Comments

Apart from leading term, number of M-sequences from multicomplexes on at most 4 variables with no monomial of degree more than n+1.
Stirling2 transform of a(n) = [1, 1, 2, 6, 26, ...] is a(n+1) = [1, 2, 6, 26, ...].
Eigensequence of Stirling2 triangle A008277. - Philippe Deléham, Mar 23 2007

References

  • S. Linusson, The number of M-sequences and f-vectors, Combinatorica, 19 (1999), 255-266.
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Cf. A048801.
Cf. A153277, A153278. - Jonathan Vos Post, Dec 22 2008

Programs

  • Maple
    stirtr:= proc(p)
               proc(n) add(p(k)*Stirling2(n,k), k=0..n) end
             end:
    a:= proc(n) option remember; `if`(n<3, 1, aa(n-1)) end:
    aa:= stirtr(a):
    seq(a(n), n=1..25);  # Alois P. Heinz, Jun 22 2012
  • Mathematica
    terms = 21; A[] = 0; Do[A[x] = Normal[Integrate[1 + A[Exp[x] - 1 + O[x]^(terms + 1)], x] + O[x]^(terms + 1)], terms];
    CoefficientList[A[x], x]*Range[0, terms]! // Rest (* Jean-François Alcover, May 23 2012, updated Jan 12 2018 *)
  • PARI
    {a(n)=local(A, E); if(n<0, 0, A=O(x); E=exp(x+x*O(x^n))-1; for(m=1, n, A=intformal( subst( 1+A, x, E+x*O(x^m)))); n!*polcoeff(A, n))} /* Michael Somos, Mar 08 2004 */
    
  • PARI
    a_vector(n) = my(v=vector(n)); v[1]=1; for(i=1, n-1, v[i+1]=sum(j=1, i, stirling(i, j, 2)*v[j])); v; \\ Seiichi Manyama, Jun 24 2022

Formula

E.g.f. A(x) satisfies A(x)' = 1+A(exp(x)-1).
G.f. satisfies: Sum_{n>=1} a(n)*x^n = x * (1 + Sum_{n>=1} a(n) * x^n / Product_{j=1..n} (1 - j*x)). - Ilya Gutkovskiy, May 09 2019
a(1) = 1; a(n+1) = Sum_{k=1..n} Stirling2(n,k) * a(k). - Seiichi Manyama, Jun 24 2022

A363007 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, 3, 6, 1, 1, 4, 13, 24, 1, 1, 5, 23, 75, 120, 1, 1, 6, 36, 175, 541, 720, 1, 1, 7, 52, 342, 1662, 4683, 5040, 1, 1, 8, 71, 594, 4048, 18937, 47293, 40320, 1, 1, 9, 93, 949, 8444, 57437, 251729, 545835, 362880, 1, 1, 10, 118, 1425, 15775, 143783, 950512, 3824282, 7087261, 3628800
Offset: 0

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Author

Seiichi Manyama, May 12 2023

Keywords

Examples

			Square array begins:
    1,   1,    1,    1,    1,     1, ...
    1,   1,    1,    1,    1,     1, ...
    2,   3,    4,    5,    6,     7, ...
    6,  13,   23,   36,   52,    71, ...
   24,  75,  175,  342,  594,   949, ...
  120, 541, 1662, 4048, 8444, 15775, ...
		

Crossrefs

Columns k=0..5 give A000142, A000670, A083355, A099391, A363008, A363009.
Main diagonal gives A363010.

Programs

  • PARI
    T(n, k) = if(k==0, 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) = n!.
T(n,k) = A153278(k,n) for n >= 1 and k >= 1.

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!.

A363009 Expansion of e.g.f. 1/(2 - exp(exp(exp(exp(exp(x) - 1) - 1) - 1) - 1)).

Original entry on oeis.org

1, 1, 7, 71, 949, 15775, 313920, 7279795, 192828745, 5744627550, 190131836270, 6921735519110, 274885665920198, 11826225289547024, 547926995688877245, 27199542114163170649, 1440220170795372833970, 81026116511855753816058
Offset: 0

Views

Author

Seiichi Manyama, May 12 2023

Keywords

Crossrefs

Row p=5 of A153278 (for n>=1).
Column k=5 of A363007.
Cf. A351428.

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, 5):
    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(exp(x)-1)-1)-1)-1))))

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) = n!.

A099391 Expansion of e.g.f. 1/(2 - exp(exp(exp(x) - 1) - 1)).

Original entry on oeis.org

1, 1, 5, 36, 342, 4048, 57437, 950512, 17975438, 382424397, 9039989107, 235062317196, 6667866337309, 204905200542916, 6781157167505291, 240446179599065951, 9094120016963808935, 365453749501228063845
Offset: 0

Views

Author

Ralf Stephan, Oct 18 2004

Keywords

Crossrefs

Column k=3 of A363007.
Row p=3 of A153278 (for n>=1).

Programs

  • Mathematica
    With[{nn=20},CoefficientList[Series[1/(2-Exp[Exp[Exp[x]-1]-1]),{x,0,nn}],x] Range[0,nn]!] (* Harvey P. Dale, Apr 10 2014 *)
  • PARI
    my(N=20, x='x+O('x^N)); Vec(serlaplace(1/(2-exp(exp(exp(x)-1)-1)))) \\ Seiichi Manyama, May 12 2023

Formula

(1/2) Sum[k=0..inf, k^n/k! * Sum[r=1..inf, e^(-r)r^k/r!*Li(-r, 1/2e) ]], with Li the polylogarithm.
a(n) ~ n! / (2 * (1 + log(2)) * (1 + log(1 + log(2))) * log(1 + log(1 + log(2)))^(n+1)). - Vaclav Kotesovec, Jun 26 2022
a(n) = Sum_{k=0..n} Stirling2(n,k) * A083355(k). - Seiichi Manyama, May 12 2023

Extensions

Definition clarified by Harvey P. Dale, Apr 10 2014

A363010 a(n) = n! * [x^n] 1/(1 - f^n(x)), where f(x) = exp(x) - 1.

Original entry on oeis.org

1, 1, 4, 36, 594, 15775, 618838, 33757864, 2448904188, 228290728635, 26617527649365, 3797508644987398, 651082351708066303, 132130157056046918808, 31333332827346731906130, 8587011712002719806274022, 2693586800519167315881703732, 958983405298849163873718493941
Offset: 0

Views

Author

Seiichi Manyama, May 12 2023

Keywords

Crossrefs

Main diagonal of A363007.
Main diagonal of A153278 (for n>=1).

Programs

  • Maple
    b:= proc(n, t, m) option remember; `if`(n=0, `if`(t<2, m!,
          b(m, t-1, 0)), m*b(n-1, t, m)+b(n-1, t, m+1))
        end:
    a:= n-> b(n$2, 0):
    seq(a(n), n=0..20);  # Alois P. Heinz, May 12 2023

Formula

a(n) = T(n,n), T(n,k) = Sum_{j=0..n} Stirling2(n,j) * T(j,k-1), k>1, T(n,0) = n!.
Showing 1-6 of 6 results.