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

1,1

Links

Table of n, a(n) for n=1..52.

Formula

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

Example

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

Mathematica

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

Crossrefs

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

Sequence in context: A267067 A322490 A351688 * A128107 A154620 A175385

Adjacent sequences: A206623 A206624 A206625 * A206627 A206628 A206629

Keyword

nonn

Author

Zak Seidov, Feb 10 2012

Status

approved