OFFSET
1,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..2500
EXAMPLE
87 is in the sequence since prime(88) - prime(87) = 457 - 449 = 8 = 2^3.
MAPLE
egcd := proc(n) local L; L:=ifactors(n)[2]; L:=map(proc(z) z[2] end, L); igcd(op(L)) end; M:=[]: cnt:=0: for z to 1 do for k from 1 to 200 do p:=ithprime(k); q:=nextprime(p); x:=q-p; if egcd(x)>1 then cnt:=cnt+1; M:=[op(M), [cnt, k, x]] fi od od; M; map(proc(z) z[3] end, M);
MATHEMATICA
f[n_] := GCD @@ Last /@ FactorInteger[n] != 1; Select[Range[200], f[Prime[ # + 1] - Prime[ # ]] &] (* Ray Chandler, Oct 19 2006 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Walter Kehowski, Jan 08 2006
EXTENSIONS
Edited by Ray Chandler, Oct 19 2006
STATUS
approved