OFFSET

1,2

COMMENTS

Equals A163578 from the second term on. - R. J. Mathar, Jun 07 2010

EXAMPLE

a(6) cannot equal 9 because both 6 and 9 are composite.

MATHEMATICA

a[n_] := a[n] = Block[{k = a[n - 1]}, If[ PrimeQ@n, k++; While[PrimeQ@k, k++ ], k = NextPrime@k]; k]; a[1] = 1; Array[a, 62] (* Robert G. Wilson v, Jun 04 2010 *)

CROSSREFS

KEYWORD

nonn

AUTHOR

J. Lowell, Jun 01 2010

EXTENSIONS

a(9) onwards from Robert G. Wilson v, Jun 04 2010

STATUS

approved