A074979 Primes for which the two closest primes are smaller.

113, 139, 181, 199, 241, 283, 293, 317, 467, 509, 523, 577, 619, 661, 773, 829, 839, 863, 887, 953, 1021, 1039, 1069, 1129, 1237, 1307, 1327, 1381, 1459, 1499, 1583, 1627, 1637, 1669, 1699, 1759, 1789, 1879, 1913, 1951, 2003, 2039, 2089, 2113, 2143

Offset: 1

Author

Neil Fernandez, Oct 10 2002

Keywords

• nonn

Examples

			The two closest primes to 113 are 109 (difference = 4) and 107 (difference = 6). Both 109 and 107 are smaller than 113, so 113 is in the list.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A001223, A074982, A075030, A075037, A075038, A075043, A075050 and A075051.

Programs

Mathematica

NextPrim[n_] := Block[{k = n + 1}, While[ !PrimeQ[k], k++ ]; k]; ps = {0, 0, 0, 1}; Do[ps = Drop[ps, 1]; ps = Append[ps, NextPrim[ ps[[ -1]]]]; If[ ps[[ -1]] - ps[[ -2]] > ps[[ -2]] - ps[[1]], Print[ ps[[ -2]]]], {n, 1, 330}]
Select[Partition[Prime[Range[400]],4,1],#[[3]]-#[[1]]<#[[4]]-#[[3]]&][[All,3]] (* Harvey P. Dale, Aug 11 2021 *)

Extensions

Edited by Robert G. Wilson v, Oct 11 2002