A124184 Positive integers not divisible by any of their own prime-factorization exponents.

1, 8, 9, 25, 32, 49, 64, 81, 121, 125, 128, 169, 225, 243, 289, 343, 361, 441, 512, 529, 625, 729, 841, 961, 1000, 1024, 1089, 1225, 1331, 1369, 1521, 1681, 1849, 2025, 2048, 2187, 2197, 2209, 2401, 2601, 2744, 2809, 3025, 3249, 3481, 3721, 3969, 4096, 4225

Offset: 1

Author

Leroy Quet, Dec 05 2006

Keywords

• nonn

Comments

If n>1 is a term then n is composite and is not squarefree. - Farideh Firoozbakht, Dec 08 2006

Examples

			18225 = 3^6 * 5^2. Neither 6 nor 2 divides 18225, so 18225 is in the sequence.
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A124438.

Programs

Mathematica

f[n_] := Times @@ Mod[n, Last /@ FactorInteger[n]] > 0;Select[Range[5000], f] (* Ray Chandler, Dec 06 2006 *)
Do[a = FactorInteger[n]; l = Length[a]; b = Table[a[[k]][[2]], {k, l}]; If[ ! MemberQ[Mod[n, b], 0], Print[n]], {n, 4000}] (* Farideh Firoozbakht, Dec 08 2006 *)

Extensions

Extended by Ray Chandler and Zak Seidov, Dec 06 2006