OFFSET
1,1
COMMENTS
A subsequence of A023202. The definition implies that the sum of the first two primes, 2(p+4), divides the sum of the product of the first two primes and the last, p(p+8)+p+20=(p+4)(p+5). This feature is shared with A022005 and common to prime triples of the format (p,p+2*a,p+a+a^2) with even a. - R. J. Mathar, Apr 26 2007
MAPLE
isA128928 := proc(n) isprime(n) and isprime(n+8) and isprime(n+20) ; end: for n from 1 to 300 do if isA128928(ithprime(n)) then printf("%d, ", ithprime(n)) ; fi ; od ; # R. J. Mathar, Apr 26 2007
MATHEMATICA
kmax = 580; Select[ Prime[ Range[1, kmax] ], (PrimeQ[ # + 8] && PrimeQ[ # + 20])& ] (* Stuart Clary *)
CROSSREFS
KEYWORD
nonn
AUTHOR
J. M. Bergot, Apr 25 2007
EXTENSIONS
STATUS
approved