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
KEYWORD
nonn
AUTHOR
Labos Elemer, Aug 06 2001
STATUS
approved