The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A346417 E.g.f.: exp(exp(2*(exp(x) - 1)) - 1). 2
 1, 2, 10, 66, 538, 5186, 57402, 714594, 9853978, 148774914, 2436823034, 42979319202, 811254807770, 16302732719682, 347248840767162, 7809649226242530, 184831773033020826, 4589793199157616770, 119272846472231229818, 3235960069037751550498, 91466308730323104617050 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Alois P. Heinz, Table of n, a(n) for n = 0..449 FORMULA a(n) = Sum_{k=0..n} Stirling2(n,k) * 2^k * Bell(k). a(0) = 1; a(n) = Sum_{k=1..n} binomial(n-1,k-1) * A001861(k) * a(n-k). MAPLE b:= proc(n, t, m) option remember; `if`(n=0, `if`(t=1, 1, b(m, 1, 0)*2^m) , m*b(n-1, t, m)+b(n-1, t, m+1)) end: a:= n-> b(n, 0\$2): seq(a(n), n=0..20); # Alois P. Heinz, Aug 06 2021 MATHEMATICA nmax = 20; CoefficientList[Series[Exp[Exp[2 (Exp[x] - 1)] - 1], {x, 0, nmax}], x] Range[0, nmax]! Table[Sum[StirlingS2[n, k] 2^k BellB[k], {k, 0, n}], {n, 0, 20}] a[0] = 1; a[n_] := a[n] = Sum[Binomial[n - 1, k - 1] BellB[k, 2] a[n - k], {k, 1, n}]; Table[a[n], {n, 0, 20}] PROG (PARI) my(x='x+O('x^25)); Vec(serlaplace(exp(exp(2*(exp(x) - 1)) - 1))) \\ Michel Marcus, Jul 19 2021 CROSSREFS Cf. A000258, A000898, A001861, A055882, A126390, A136658. Sequence in context: A060206 A277493 A361448 * A108205 A228938 A245000 Adjacent sequences: A346414 A346415 A346416 * A346418 A346419 A346420 KEYWORD nonn AUTHOR Ilya Gutkovskiy, Jul 16 2021 STATUS approved

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

Last modified March 26 13:22 EDT 2023. Contains 361549 sequences. (Running on oeis4.)