OFFSET
1,1
LINKS
Donovan Johnson, Table of n, a(n) for n = 1..1000
FORMULA
prime(n) - n = q^k, q is prime and k_Integer >= 2.
EXAMPLE
690 is OK because prime(690)-690 = 5179-690 = 4489 = 67^2, 67 is prime.
MATHEMATICA
lst = {}; fQ[n_] := Block[{pf=FactorInteger[n]}, (2-Length[pf])(pf[[1, 2]]-1) > 0]; Do[ If[ fQ[Prime[n] - n], Print[n]; AppendTo[lst, n]], {n, 3, 362439}]; lst
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov and Robert G. Wilson v, May 22 2005
STATUS
approved