OFFSET
1,2
COMMENTS
Numbers in this sequence but not in A140973 are 2021 and 2090 (but no others below 8400). - Emeric Deutsch, Aug 19 2008.
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1500
FORMULA
{n: n | A008937(n-2)}.
MAPLE
A000073 := proc(n) option remember ; if n <= 1 then 0 ; elif n =2 then 1 ; else procname(n-1)+procname(n-2)+procname(n-3) ; fi; end: A008937 := proc(n) option remember ; add(A000073(i), i=0..n+1) ; end: isA := proc(n) if n = 1 then RETURN(true) ; fi; if A008937(n-2) mod n = 0 then true; else false ; fi; end: for n from 1 to 2000 do if isA(n) then printf("%d, ", n) ; fi; od ;
MATHEMATICA
Module[{nn=1300, tnos}, tnos=LinearRecurrence[{1, 1, 1}, {0, 0, 1}, nn]; Position[ Table[Mean[Take[tnos, n]], {n, nn}], _?(IntegerQ[#]&)]]//Flatten (* Harvey P. Dale, Oct 05 2020 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
R. J. Mathar, Aug 19 2008
STATUS
approved