This site is supported by donations to The OEIS Foundation.



The OEIS Foundation is grateful to everyone who made a donation during our Annual Appeal.     Visit the new and spectacular Pictures from the OEIS page!

(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A128928 Smallest member p of a triple of primes (p,p+8,p+20). 0


%S 3,11,23,53,59,89,131,173,191,263,359,389,401,479,593,599,653,719,

%T 1013,1031,1109,1193,1229,1283,1439,1451,1523,1559,1601,1733,1979,

%U 2273,2531,2663,2699,2711,3041,3209,3251,3299,3323,3449,3491,3539,3623,3719,3911,3923,4091,4211

%N Smallest member p of a triple of primes (p,p+8,p+20).

%C 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

%p 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

%t kmax = 580; Select[ Prime[ Range[1, kmax] ], (PrimeQ[ # + 8] && PrimeQ[ # + 20])& ] (* _Stuart Clary_ *)

%Y Cf. A022005.

%K nonn

%O 1,1

%A _J. M. Bergot_, Apr 25 2007

%E Corrected and extended by _Robert G. Wilson v_, _R. J. Mathar_ and _Stuart Clary_, Apr 26 2007

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified February 14 00:48 EST 2016. Contains 268318 sequences.