A063091 Prime(n) such that gcd(1+prime(n+1), 1+prime(n)) = gcd(-1+prime(n+1), -1+prime(n)).

2, 3, 5, 11, 17, 29, 41, 59, 71, 101, 107, 137, 149, 179, 191, 197, 227, 239, 269, 281, 283, 311, 317, 337, 347, 419, 431, 461, 521, 547, 569, 577, 599, 617, 641, 659, 773, 787, 809, 821, 827, 857, 863, 881, 1019, 1031, 1049, 1061, 1091, 1129, 1151, 1153

Offset

1,1

Links

Harry J. Smith, Table of n, a(n) for n = 1..1000

Example

p=101 is here because gcd(102,104) = 2 = gcd(100,102).

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 (* Vladimir Joseph Stephan Orlovsky, Apr 11 2010 *)
Transpose[Select[Partition[Prime[Range[200]], 2, 1], GCD[First[#]+1, Last[#]+1] == GCD[First[#]-1, Last[#]-1]&]][[1]] (* Harvey P. Dale, Jan 22 2012 *)

Prog

(PARI) { n=0; for (m=1, 10^9, if(gcd(prime(m+1) + 1, prime(m) + 1) == gcd(prime(m+1) - 1, prime(m) - 1), write("b063091.txt", n++, " ", prime(m)); if (n==1000, break)) ) } \\ Harry J. Smith, Aug 17 2009

Crossrefs

Cf. A058263.

Sequence in context: A318786 A038909 A073534 * A124588 A059428 A084571

Adjacent sequences: A063088 A063089 A063090 * A063092 A063093 A063094

Keyword

nonn

Author

Labos Elemer, Aug 06 2001

Status

approved