A192681 Floor-sqrt transform of Lah partition numbers (A000262).

1, 1, 1, 3, 8, 22, 63, 193, 627, 2143, 7677, 28706, 111669, 450529, 1880164, 8097765, 35922614, 163849371, 767224522, 3682984346, 18102428784, 91000840873, 467393250911, 2450438244585, 13102651355735, 71398380128514, 396202573696587

Offset: 0

Author

Emanuele Munarini, Jul 07 2011

Keywords

• nonn

Programs

Maple

A000262 := proc(n) option remember: if n=0 then RETURN(1) fi: if n=1 then RETURN(1) fi: (2*n-1)*procname(n-1) - (n-1)*(n-2)*procname(n-2) end proc:
A192681 := proc(n) floor(sqrt(A000262(n))) ; end proc: # R. J. Mathar, Jul 13 2011

Mathematica

FSFromExpSeries[f_,x_,n_] := Map[Floor[Sqrt[#]]&,CoefficientList[Series[f,{x,0,n}],x]Table[k!,{k,0,n}]]
FSFromExpSeries[Exp[x/(1-x)],x,60]

Formula

a(n) = floor(sqrt(A000262(n))).

Extensions

All terms replaced by R. J. Mathar, Jul 13 2011