A102744 - OEIS

A102744

Integers that do not appear in the sequence (A102722) given by the floor of the sum of {n/k} while k=1,...,n. Here {x}:=x-[x].

%I #8 Mar 29 2015 16:17:03

%S 3,12,37,57,60,70,75,85,89,92,131,147,161,166,177,181,182,194,200,211,

%T 224,228,233,242,244,255,259,260,265,269,271,281,285,293,294,321,325,

%U 329,336,343,364,367,394,402,415,425,435,445,464,465,484,499,522,531

%N Integers that do not appear in the sequence (A102722) given by the floor of the sum of {n/k} while k=1,...,n. Here {x}:=x-[x].

%t Resto = Function[n, Sum[n/k - Floor[n/k], {k, 1, n}]]; oops = Floor[Map[Resto, Range[1, 10000]]]; Complement[Range[Max[oops]], Union[oops]]

%t f[n_] := Floor[Plus @@ FractionalPart[n/Range[2, n - 1]]]; t = {}; Do[ a = f[n]; If[ Position[t, a] == {}, AppendTo[t, a]], {n, 1500}]; Take[ Complement[ Range[ Max[ t]], t], 60] (* _Robert G. Wilson v_, Feb 19 2005 *)

%Y Cf. A103504. This is the complement of A102722.

%K nonn

%O 1,1

%A _Carlos Alves_, Feb 08 2005

%E Edited and corrected by _Robert G. Wilson v_, Feb 19 2005