OFFSET
1,1
COMMENTS
Primes q such that q+4 is in A006450. - Robert Israel, Nov 09 2020
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
Prime(13) = 41. 41 - 4 = 37.
MAPLE
R:= NULL: p:= 7:
for i from 5 to 10000 do
q:= p; p:= nextprime(p);
if isprime(i) and q=p-4 then R:= R, q fi;
od:
R; # Robert Israel, Nov 09 2020
MATHEMATICA
Prime[#]&/@Select[Prime[Range[2, 300]], PrimeQ[Prime[#]-4]&]-4 (* Harvey P. Dale, May 21 2021 *)
PROG
(PARI) a(n) = { forprime(x=2, n, y=prime(x)- 4; if(isprime(y), print1(y", ")) ) }
CROSSREFS
KEYWORD
nonn
AUTHOR
Cino Hilliard, May 31 2004
EXTENSIONS
Definition corrected by Robert Israel, Nov 09 2020
STATUS
approved