This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A144792 EXP transform of A140585. 2
 1, 1, 5, 33, 282, 2938, 36029, 507440, 8058990, 142315830, 2763775025, 58498072273, 1339545500214, 32980132065364, 868417100538399, 24344702489881998, 723694354351500431, 22733368105181643193, 752291980101845144878, 26153153055424960528533 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS Stirling transform of A143463. LINKS Alois P. Heinz, Table of n, a(n) for n = 0..200 FORMULA E.g.f: (1/exp(1)) exp( 1 / prod_{k=1}^{inf} (1 - (exp(x)-1)^k / k!) ). a(n) = sum_{k=1..n} C(n-1,k-1) A140585(k) a(n-k). With S2(n,k) as the Stirling number of the second kind we have a(n) = sum_{k=1..n} A143463(n) S2(n,k). MAPLE with(numtheory): with(combinat): b:= proc(k) option remember; add(d/d!^(k/d), d=divisors(k)) end: c:= proc(n) option remember; `if`(n=0, 1, add((n-1)!/(n-k)!* b(k)* c(n-k), k=1..n)) end: aa:= n-> add(stirling2(n, k) *c(k), k=1..n): a:= proc(n) option remember; `if`(n=0, 1, aa(n)+ add(binomial(n-1, k-1) *aa(k) *a(n-k), k=1..n-1)) end: seq(a(n), n=1..20); # Alois P. Heinz, Oct 10 2008 MATHEMATICA b[k_] := b[k] = DivisorSum[k, #/#!^(k/#)&]; c[n_] := c[n] = If[n==0, 1, Sum[(n-1)!/(n-k)!*b[k]*c[n-k], {k, 1, n}]]; aa[n_] := Sum[StirlingS2[n, k]*c[k], {k, 1, n}]; a[n_] := a[n] = If[n==0, 1, aa[n] + Sum[Binomial[ n-1, k-1]*aa[k]*a[n-k], {k, 1, n-1}]]; Table[a[n], {n, 0, 20}] (* Jean-François Alcover, Feb 25 2017, after Alois P. Heinz *) CROSSREFS Cf. A140585, A143463. Sequence in context: A316158 A120733 A218496 * A291846 A255927 A001828 Adjacent sequences:  A144789 A144790 A144791 * A144793 A144794 A144795 KEYWORD nonn AUTHOR Thomas Wieder, Sep 21 2008 EXTENSIONS More terms from Alois P. Heinz, Oct 10 2008 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified August 20 10:01 EDT 2019. Contains 326143 sequences. (Running on oeis4.)