A075050 Primes for which the eight closest primes are smaller.

15683, 31397, 43801, 44293, 89689, 221101, 248909, 265621, 282713, 341357, 349423, 370261, 396733, 399283, 404851, 440581, 492113, 517639, 520451, 542603, 544031, 561109, 566453, 566567, 576791, 604073, 626629, 639757, 673669, 678659

Offset: 1

Author

Neil Fernandez, Oct 10 2002

Keywords

• nonn

Examples

			The eight closest primes to 15683 are 15679 (difference = 4), 15671 (difference = 12), 15667 (difference = 16), 15661 (difference = 22), 15649 (difference = 34), 15647 (difference = 36), 15643 (difference = 40) and 15641 (difference = 42). These are all smaller than 15683 so 15683 is in the list.
		

Links

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

Crossrefs

Cf. A001223, A074979, A074982, A075030, A075037, A075038, A075043 and A075051.

Programs

Mathematica

NextPrim[n_] := Block[{k = n + 1}, While[ !PrimeQ[k], k++ ]; k]; ps = {0, 0, 0, 0, 0, 0, 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, 58393}]
Select[Partition[Prime[Range[55000]],10,1],#[[9]]-#[[1]]<#[[10]]-#[[9]]&][[All,9]] (* Harvey P. Dale, Feb 20 2022 *)

Extensions

Edited and extended by Robert G. Wilson v, Oct 11 2002