A176182 Primes p(n) such that gcd(p(n)-1, p(n+1)-1) < gcd(p(n)+1, p(n+1)+1).

7, 19, 23, 43, 47, 53, 67, 79, 83, 103, 127, 131, 139, 163, 167, 173, 223, 233, 251, 257, 263, 293, 307, 353, 359, 379, 383, 409, 439, 443, 463, 467, 479, 487, 491, 499, 503, 509, 557, 563, 587, 593, 643, 647, 653, 677, 683, 709, 719, 739, 743, 797, 823, 829

Offset

1,1

Links

Table of n, a(n) for n=1..54.

Mathematica

lst={}; Do[p0=Prime[n]; p1=Prime[n+1]; If[GCD[p0-1, p1-1]<GCD[p0+1, p1+1], AppendTo[lst, p0]], {n, 6!}]; lst
Transpose[Select[Partition[Prime[Range[150]], 2, 1], GCD[First[#]-1, Last[#]-1]<GCD[First[#]+1, Last[#]+1]&]][[1]] (* Harvey P. Dale, Jul 06 2011 *)

Crossrefs

Cf. A063091, A176180, A176181.

Sequence in context: A353046 A032680 A141831 * A292349 A065749 A032642

Adjacent sequences: A176179 A176180 A176181 * A176183 A176184 A176185

Keyword

nonn

Author

Vladimir Joseph Stephan Orlovsky, Apr 11 2010

Status

approved