OFFSET
1,1
COMMENTS
The sequence is defined recursively. The complement of A227007.
LINKS
FORMULA
a(n) = n + 16 for n > 1791. - Charles R Greathouse IV, Jun 27 2013
MATHEMATICA
Needs["NumberTheory`NumberTheoryFunctions`"]; Property[2] = False; Property[{}] = False; Property[n_] := Property[n] = If[ListQ[n], Property[n[[1, 1]]] || Property[Rest[n]], SquareFreeQ[n - 1] == False || Property[fa[n - 1]]]; Select[1 + Range[100], Property]
PROG
(PARI) is(n)=if(n<7, return(n>4)); if(n>1807 || !issquarefree(n-1), return(1)); fordiv(n-1, d, if(isprime(d) && is(d), return(1))); 0 \\ Charles R Greathouse IV, Nov 13 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
José María Grau Ribas, Jun 27 2013
EXTENSIONS
Definition corrected by Charles R Greathouse IV, Nov 13 2013
STATUS
approved