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.

A182932 Generalized Bell numbers, row 3 of A182933.

Original entry on oeis.org

1, 13, 778, 104149, 25053583, 9566642254, 5355754528213, 4158610032552331, 4298349730542075004, 5729540573235706713253, 9603970716624058765049701, 19831898899231255981742972188, 49594487447520772034033468182501
Offset: 0

Views

Author

Peter Luschny, Mar 29 2011

Keywords

Crossrefs

Programs

  • Maple
    A182932 := proc(n) local r,s,i; r := [seq(4,i=1..n)]; s := [seq(1,i=1..n-1),2]; exp(-x)*6^n*hypergeom(r,s,x); round(evalf(subs(x=1,%),66)) end:
    seq(A182932(n),n=0..12);
  • Mathematica
    a[n_] := 3!^n*HypergeometricPFQ[ Table[4, {n}], Append[ Table[1, {n-1}], 2], 1.`40.]/E; Table[Round[a[n]], {n, 0, 12}] (* Jean-François Alcover, Jul 29 2013 *)

Formula

Let r = [4,...,4] (n occurrences of 4), s = [1,...,1,2] (n-1 occurrences of 1)
and F_n the generalized hypergeometric function of type n_F_n, then
a(n) = exp(-1)*3!^n*F_n(r,s |1).
e.g.f.: Sum_{j>=0}(exp((j+2)!/(j-1)!*x-1)/j!).

A182934 Generalized Bell numbers, column 2 of A182933.

Original entry on oeis.org

1, 2, 27, 778, 37553, 2688546, 265141267, 34260962282, 5594505151713, 1123144155626338, 271300013006911211, 77489174023697484522, 25797166716252173322577, 9890278784047791697198658, 4322087630240844404678150883
Offset: 0

Views

Author

Peter Luschny, Mar 29 2011

Keywords

Crossrefs

Programs

  • Maple
    A182934 := proc(n)
    exp(-x)*n!^2*hypergeom([n+1,n+1],[1,2],x); round(evalf(subs(x=1,%),66)) end:
    seq(A182934(n),n=0..14);
  • Mathematica
    a[n_] := n!^2*HypergeometricPFQ[{n+1, n+1}, {1, 2}, 1.`40.]/E; Table[a[n] // Round, {n, 0, 14}] (* Jean-François Alcover, Jul 29 2013 *)

Formula

a(n) = exp(-1)*n!^2*F_2([n+1,n+1],[1,2] |1), F_2 the generalized hypergeometric function of type 2_F_2.
Let b_{n}(x) = Sum_{j>=0}(x*exp((j+n-1)!/(j-1)!-1)/j!) then a(n) = 2 [x^2] series b_{n}(x), where [x^2] denotes the coefficient of x^2 in the Taylor series for b_{n}(x).

A090210 Triangle of certain generalized Bell numbers.

Original entry on oeis.org

1, 1, 1, 2, 1, 1, 5, 7, 1, 1, 15, 87, 34, 1, 1, 52, 1657, 2971, 209, 1, 1, 203, 43833, 513559, 163121, 1546, 1, 1, 877, 1515903, 149670844, 326922081, 12962661, 13327, 1, 1, 4140, 65766991, 66653198353, 1346634725665, 363303011071, 1395857215, 130922, 1, 1
Offset: 1

Views

Author

Wolfdieter Lang, Dec 01 2003

Keywords

Comments

Let B_{n}(x) = sum_{j>=0}(exp(j!/(j-n)!*x-1)/j!) and
S(n,k) = k! [x^k] taylor(B_{n}(x)), where [x^k] denotes the
coefficient of x^k in the Taylor series for B_{n}(x).
Then S(n,k) (n>0, k>=0) is the square array representation of the triangle.
To illustrate the cross-references of T(n,k) when written as a square array.
0: A000012: 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, ...
1: A000110: 1, 1, 2, 5, 15, 52, 203, 877, 4140, ...
2: A020556: 1, 1, 7, 87, 1657, 43833, 1515903, ...
3: A069223: 1, 1, 34, 2971, 513559, 149670844, ...
4: A071379: 1, 1, 209, 163121, 326922081, ...
5: A090209: 1, 1, 1546, 12962661, 363303011071,...
6: ... 1, 1, 13327, 1395857215, 637056434385865,...
Note that the sequence T(0,k) is not included in the data.
- Peter Luschny, Mar 27 2011

Examples

			Triangle begins:
1;
1, 1;
2, 1, 1;
5, 7, 1, 1;
15, 87, 34, 1, 1;
52, 1657, 2971, 209, 1, 1;
203, 43833, 513559, 163121, 1546, 1, 1;
		

References

  • P. Blasiak, K. A. Penson and A. I. Solomon, The general boson normal ordering problem, Phys. Lett. A 309 (2003) 198-205.
  • M. Schork, On the combinatorics of normal ordering bosonic operators and deforming it, J. Phys. A 36 (2003) 4651-4665.

Crossrefs

Programs

  • Maple
    A090210_AsSquareArray := proc(n,k) local r,s,i;
    if k=0 then 1 else r := [seq(n+1,i=1..k-1)]; s := [seq(1,i=1..k-1)];
    exp(-x)*n!^(k-1)*hypergeom(r,s,x); round(evalf(subs(x=1,%),99)) fi end:
    seq(lprint(seq(A090210_AsSquareArray(n,k),k=0..6)),n=0..6);
    # Peter Luschny, Mar 30 2011
  • Mathematica
    t[n_, k_] := t[n, k] = Sum[(n+j)!^(k-1)/(j!^k*E), {j, 0, Infinity}]; t[_, 0] = 1;
    Flatten[ Table[ t[n-k+1, k], {n, 0, 8}, {k, n, 0, -1}]][[1 ;; 43]] (* Jean-François Alcover, Jun 17 2011 *)

Formula

a(n, m) = Bell(m;n-(m-1)), n>= m-1 >=0, with Bell(m;k) := Sum_{p=m..m*k} S2(m;k, p), where S2(m;k, p) := (((-1)^p)/p!) * Sum_{r=m..p} ((-1)^r)*binomial(p, r)*fallfac(r, m)^k; with fallfac(n, m) := A008279(n, m) (falling factorials) and m<=p<=k*m, k>=1, m=1, 2, ..., else 0. From eqs.(6) with r=s->m and eq.(19) with S_{r, r}(n, k)-> S2(r;n, k) of the Blasiak et al. reference. [Corrected by Sean A. Irvine, Jun 03 2024]
a(n, m) = (Sum_{k>=m} fallfac(k, m)^(n-(m-1)))/exp(1), n>=m-1>=0, else 0. From eq.(26) with r->m of the Schork reference which is rewritten eq.(11) of the original Blasiak et al. reference.
E.g.f. m-th column (no leading zeros): (Sum_{k>=m} exp(fallfac(k, m)*x)/k!) + A000522(m)/m!)/exp(1). Rewritten from the top of p. 4656 of the Schork reference.

A308537 a(n) = exp(-1) * Sum_{k>=0} (k + n - 1)!^n/(k!*(k - 1)!^n).

Original entry on oeis.org

1, 1, 27, 104149, 192052025697, 401307330353526478576, 1891640643805444860923624673784723, 35720630453521390599442254755998585843785410691847, 4425335738067265257031641848982502946902371654704454173556393591653249
Offset: 0

Views

Author

Ilya Gutkovskiy, Jun 06 2019

Keywords

Crossrefs

Main diagonal of A182933.

Programs

  • Mathematica
    Table[Exp[-1] Sum[(k + n - 1)!^n/(k! (k - 1)!^n), {k, 0, Infinity}], {n, 0, 8}]

Formula

a(n) = A182933(n,n).
Showing 1-4 of 4 results.