login
Primes for which the five closest primes are smaller.
7

%I #15 May 19 2019 11:37:00

%S 1327,3469,9439,12119,13187,14563,15683,15823,19609,21031,21617,22307,

%T 22573,23689,25261,25471,29033,29881,31277,31397,32803,33647,34061,

%U 35543,35617,38461,39251,40289,40639,42863,43331,43801,44293,45139

%N Primes for which the five closest primes are smaller.

%e The five closest primes to 1327 are 1321 (difference = 6), 1319 (difference = 8), 1307 (different = 20), 1303 (difference = 24) and 1301 (difference =26). 1321, 1319, 1307, 1303 and 1301 are all smaller than 1327, so 1327 is in the list.

%t okQ[n_]:=Module[{p5=Prime[PrimePi[n]-5],pp=NextPrime[n]},(n-p5)<(pp-n)]; Select[Prime[Range[6,5000]],okQ] (* _Harvey P. Dale_, Jan 17 2011 *)

%t ps={2,3,5,7,11}; p=13; Reap[Do[np=NextPrime[p]; If[p-ps[[1]] < np-p, Sow[p]]; ps=RotateLeft[ps]; ps[[-1]]=p; p=np, {5000}]][[2,1]]

%Y Cf. A001223, A074979, A074982, A075030, A075038, A075043, A075050 and A075051.

%K nonn

%O 1,1

%A _Neil Fernandez_, Oct 10 2002

%E Edited by _Robert G. Wilson v_, Oct 11 2002