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A173144 Numbers n such that neither prime(n-1) nor prime(n+1) is of form 6k+1. 1
2, 4, 6, 8, 14, 16, 25, 27, 29, 31, 34, 40, 42, 44, 50, 53, 55, 56, 61, 63, 65, 70, 78, 80, 82, 88, 90, 93, 95, 97, 103, 108, 117, 119, 125, 127, 136, 138, 141, 143, 145, 147, 149, 151, 153, 155, 157, 159, 161, 163, 165, 172, 177, 183, 185, 191, 193, 195, 200, 207 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

A000040(a(n))=A171817(m).

EXAMPLE

a(1)=2 because prime(2-1)=2 and prime(2+1)=5 are not of form 6k+1.

MATHEMATICA

f6kQ[n_]:=And@@(!IntegerQ[(#-1)/6]&/@{Prime[n-1], Prime[n+1]}); Select[ Range[2, 300], f6kQ] (* Harvey P. Dale, Feb 29 2012 *)

CROSSREFS

Cf. A002476, A171817.

Sequence in context: A152973 A089747 A274170 * A049015 A005250 A162762

Adjacent sequences:  A173141 A173142 A173143 * A173145 A173146 A173147

KEYWORD

nonn,easy,less

AUTHOR

Juri-Stepan Gerasimov, Feb 11 2010

EXTENSIONS

1 removed by Charles R Greathouse IV, Mar 25 2010

STATUS

approved

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Last modified September 21 12:13 EDT 2020. Contains 337271 sequences. (Running on oeis4.)