OFFSET
1,2
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
MATHEMATICA
fa = FactorInteger; Gu[n_] := Union@Table[IntegerQ[(n + 1)/(fa[n][[i, 1]] - 1)], {i, Length[fa[n]]}]; Select[Range[20000], Gu[#] == {False} &]
Join[{1}, Select[Range[2, 300], NoneTrue[(#+1)/(FactorInteger[#][[All, 1]]-1), IntegerQ]&]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Mar 08 2019 *)
PROG
(PARI) isok(n) = {my(f=factor(n)[, 1]); for (k=1, #f~, if (!((n+1) % (f[k]-1)), return(0)); ); return(1); } \\ Michel Marcus, Oct 02 2019
(Magma) [1] cat [k: k in [2..220]| #[p:p in PrimeDivisors(k)| IsIntegral((k+1)/(p-1))] eq 0]; // Marius A. Burtea, Oct 02 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
José María Grau Ribas, Jan 20 2014
EXTENSIONS
Term 1 prepended by Max Alekseyev, Jan 20 2014
STATUS
approved