A318959 Primes p (> 2) such that p - 2 and p - 1 are nonsquarefree.

29, 101, 127, 137, 149, 173, 277, 281, 317, 353, 389, 461, 509, 541, 569, 577, 641, 677, 727, 821, 857, 877, 929, 977, 1109, 1129, 1181, 1217, 1277, 1289, 1361, 1423, 1433, 1451, 1613, 1667, 1721, 1777, 1861, 1877, 1901, 1913, 1973, 2081, 2153, 2297, 2333, 2351

Offset: 1

Author

Seiichi Manyama, Sep 06 2018

Keywords

• nonn

Examples

			21 (= 23 - 2) is squarefree. So 23 is not a term.
27 = 3^3 and 28 = 2^2*7. So 29 is a term.
		

Links

• Seiichi Manyama, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000040, A039787, A049231, A240473, A257545, A319049.

Programs

Magma

[p: p in PrimesInInterval(3, 2500)| not IsSquarefree(p-2) and not IsSquarefree(p-1)]; // Vincenzo Librandi, Sep 06 2018

Mathematica

Select[Prime[Range[500]], !SquareFreeQ[# - 2] && !SquareFreeQ[# - 1] &] (* Vincenzo Librandi, Sep 06 2018 *)

PARI

forprime(p=2, 1e4, if(!issquarefree(p-1)&&!issquarefree(p-2), print1(p, ", "))); \\ Altug Alkan, Sep 06 2018