login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A128928 Smallest member p of a triple of primes (p,p+8,p+20). 0
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 (list; graph; refs; listen; history; text; internal format)
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

LINKS

Table of n, a(n) for n=1..50.

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

Cf. A022005.

Sequence in context: A335677 A248348 A173078 * A289888 A145477 A243887

Adjacent sequences:  A128925 A128926 A128927 * A128929 A128930 A128931

KEYWORD

nonn

AUTHOR

J. M. Bergot, Apr 25 2007

EXTENSIONS

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

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 7 13:24 EST 2021. Contains 341886 sequences. (Running on oeis4.)