OFFSET
1,1
COMMENTS
Conjecture: The sequence is infinite and for every n, a(n+1) < a(n)^(1+1/n). Namely a(n)^(1/n) is a strictly decreasing function of n (see comment lines of the sequence A248855). - Jahangeer Kholdi and Farideh Firoozbakht, Nov 29 2014
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
MAPLE
for i from 1 to 446 do if ithprime(i+1) = ithprime(i) + 8 then print({ithprime(i)}); fi; od; # Zerinvary Lajos, Mar 19 2007
p:=ithprime; nx:=nextprime; f:=proc(d) global p, nx; local i, t0, n; t0:=[]; for n from 1 to 100000 do i:=p(n); if nx(i)-i=d then t0:=[op(t0), i]; fi; od: t0; end; f(8); # N. J. A. Sloane, Jan 17 2012
MATHEMATICA
Transpose[Select[Partition[Prime[Range[500]], 2, 1], Last[#] - First[#] == 8 &]][[1]] (* Bruno Berselli, Apr 09 2013 *)
PROG
(Magma) [p: p in PrimesUpTo(4000) | NextPrime(p)-p eq 8]; // Bruno Berselli, Apr 09 2013
(PARI) is_A031926(p)={precprime(p-1)==p-8 && isprime(p)} \\ M. F. Hasler, Apr 20 2013
(PARI) q=0; forprime(p=1, 5000, q+8==(q=p)&&print1(p-8", ")) \\ M. F. Hasler, Apr 20 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved