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A075043 Primes for which the seven closest primes are smaller. 8
15683, 25471, 31397, 43801, 44293, 69499, 89689, 102701, 124367, 142993, 155921, 162293, 166871, 172441, 183527, 193891, 196201, 198859, 203461, 206827, 212701, 221101, 225167, 225383, 248909, 256219, 259033, 265621, 282713, 288583, 290249 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

If 9 consecutive primes are p1, p2, p3 ... p9, p8 is included in the sequence if p8-p1 is less than p9-p8. - Harvey P. Dale, Mar 25 2013

LINKS

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

EXAMPLE

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

MATHEMATICA

NextPrim[n_] := Block[{k = n + 1}, While[ !PrimeQ[k], k++ ]; k]; ps = {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, 26185}]

Transpose[Select[Partition[Prime[Range[25000]], 9, 1], #[[8]]-#[[1]]<#[[9]]- #[[8]]&]][[8]](* Harvey P. Dale, Mar 25 2013 *)

CROSSREFS

Cf. A001223, A074979, A074982, A075030, A075037, A075038, A075050 and A075051.

Sequence in context: A195814 A165612 A206747 * A109567 A075050 A134121

Adjacent sequences:  A075040 A075041 A075042 * A075044 A075045 A075046

KEYWORD

nonn

AUTHOR

Neil Fernandez, Oct 10 2002

EXTENSIONS

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

STATUS

approved

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Last modified April 20 17:14 EDT 2021. Contains 343135 sequences. (Running on oeis4.)