A206626 Primes p such that p + previousprime(p) is a squarefree number.

3, 17, 23, 41, 71, 97, 107, 113, 131, 167, 197, 211, 223, 233, 311, 383, 397, 401, 457, 467, 479, 487, 491, 503, 521, 617, 647, 673, 691, 709, 727, 743, 761, 773, 809, 863, 881, 887, 907, 919, 937, 941, 971, 991, 1009, 1013, 1097, 1117, 1171, 1213, 1249, 1283

Offset: 1

Author

Zak Seidov, Feb 10 2012

Keywords

• nonn

Examples

			3+2 = 5 = A206462(1), 17+13 = 30 = A206462(2).
		

Crossrefs

Cf. A001043, A001358, A005117, A206329, A206462.

Programs

Mathematica

Select[Prime[Range[250]],SquareFreeQ[#+NextPrime[#,-1]]&] (* Harvey P. Dale, Sep 21 2023 *)

Formula

a(n) = A206329(n) - A206462 (n).