OFFSET
1,2
COMMENTS
Lambda(n) is the Carmichael lambda function (A002322).
EXAMPLE
The divisors of 140 are 1, 2, 4, 5, 7, 10, 14, 20, 28, 35, 70, 140 and lambda(140) = 12 = 1 + 2 + 4 + 5; hence 140 belongs to the sequence.
MAPLE
with(numtheory):for n from 1 to 2500 do:x:=divisors(n):n1:=nops(x):s:=0:for k from 1 to n1 while(s<=n) do:s:=s+x[k]:if s= lambda(n) then printf(`%d, `, n):else fi:od:od:
MATHEMATICA
Select[Range[2000], MemberQ[FoldList[Plus, 0, Divisors[#]], CarmichaelLambda[#]] &] (* T. D. Noe, Aug 29 2011 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Michel Lagneau, Aug 28 2011
STATUS
approved