OFFSET
1,2
COMMENTS
Same as A122537, except that a(n) is allowed to be less than a(n-1) (but not equal to it, or any other previous term).
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..1000
MAPLE
a:=array(0..100000); m:=array(0..100000); hit:=array(0..100000); B:=100000; M:=120;
for n from 1 to B do hit[n]:=0; od:
a[1]:=1; m[1]:=1; a[2]:=4; m[2]:=2; hit[2]:=1; hit[5]:=1; hit[8]:=1; hit[1]:=1; hit[4]:=1;
for n from 3 to M do i:=n; while hit[i] = 1 do i:=i+n; od; a[n]:= i; m[n]:= i/n; hit[i]:=1;
for j from 1 to n do hit[a[j]+i]:=1; od; od:
t1:=[seq(a[n], n=1..M)]; t2:=[seq(m[n], n=1..M)];
MATHEMATICA
f[s_] := Block[{n, k}, k = n = Length[s] + 1; While[MemberQ[Union[s, Plus @@@ Tuples[s, 2]], k], k += n]; Append[s, k]]; Nest[f, {1}, 60] (* Ray Chandler, Sep 29 2006 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Sep 20 2006
STATUS
approved