A107607 Numbers n such that prime(n) - n is a perfect power.

1, 2, 12, 15, 38, 39, 100, 118, 152, 190, 212, 258, 352, 462, 542, 690, 741, 746, 1285, 1396, 1417, 1632, 2119, 2243, 2318, 2603, 3370, 3777, 4073, 4155, 4485, 4522, 4600, 4719, 5317, 5446, 6697, 6748, 6985, 7144, 7520, 7595, 9492, 9551, 12010, 12985

Offset: 1

Author

Zak Seidov, May 17 2005

Keywords

• nonn

Examples

			Prime(12) - 12 = 37 - 12 = 25 = 5^2.
		

Crossrefs

Cf. A001597 (perfect powers), A107605, A107606, A107608 (associated prime(n)-n).

Programs

Mathematica

f[n_] := Prime[n] - n; Select[Range[10^4], ! GCD @@ Last /@ FactorInteger[f[ # ]] == 1 &] (* Ray Chandler, May 21 2005 *)

PARI

isA107607(n)=(ispower(prime(n)-n) > 1) || (prime(n)-n == 1) \\ Michael B. Porter, Sep 28 2009

Extensions

Extended by Ray Chandler, May 21 2005