OFFSET
1,1
COMMENTS
All terms = {11,17} mod 30.
a(n) + 20 is the greatest term in the sequence of 5 consecutive primes with 4 consecutive gaps 2, 4, 6, 8. - Muniru A Asiru, Aug 03 2017
LINKS
Zak Seidov, Table of n, a(n) for n = 1..2000
EXAMPLE
Prime(69..73) = {347, 349, 353, 359, 367} and 349 - 347 = 2, 353 - 349 = 4, 359 - 353 = 6, 367 - 359 = 8.
MAPLE
N:= 10^6: # to get all terms <= N
Primes:= select(isprime, [seq(i, i=3..N+20, 2)]):
Primes[select(t -> [Primes[t+1]-Primes[t], Primes[t+2]-Primes[t+1], Primes[t+3]-Primes[t+2], Primes[t+4]-Primes[t+3]] = [2, 4, 6, 8], [$1..nops(Primes)-4])]; # Robert Israel, Aug 03 2017
MATHEMATICA
d = Differences[Prime[Range[100000]]]; Prime[Flatten[Position[Partition[d, 4, 1], {2, 4, 6, 8}]]] (* T. D. Noe, May 23 2011 *)
Select[Partition[Prime[Range[31000]], 5, 1], Differences[#]=={2, 4, 6, 8}&][[All, 1]] (* Harvey P. Dale, Jul 03 2020 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov, May 20 2011
EXTENSIONS
Additional cross references from Harvey P. Dale, May 10 2014
STATUS
approved