A128928 Smallest member p of a triple of primes (p,p+8,p+20).

3, 11, 23, 53, 59, 89, 131, 173, 191, 263, 359, 389, 401, 479, 593, 599, 653, 719, 1013, 1031, 1109, 1193, 1229, 1283, 1439, 1451, 1523, 1559, 1601, 1733, 1979, 2273, 2531, 2663, 2699, 2711, 3041, 3209, 3251, 3299, 3323, 3449, 3491, 3539, 3623, 3719, 3911, 3923, 4091, 4211

Offset: 1

Author

J. M. Bergot, Apr 25 2007

Keywords

• nonn

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

Crossrefs

Cf. A022005.

Programs

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 *)

Extensions

Corrected and extended by Robert G. Wilson v, R. J. Mathar and Stuart Clary, Apr 26 2007