A173145 - OEIS

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A173145

Numbers n such that neither prime(n-1) nor prime(n+1) is of form 6k-1.

3, 5, 7, 13, 20, 26, 28, 30, 35, 37, 43, 45, 47, 49, 60, 62, 64, 66, 69, 74, 79, 81, 83, 89, 94, 100, 111, 113, 116, 126, 128, 130, 132, 135, 137, 142, 144, 146, 148, 150, 152, 154, 156, 158, 168, 173, 176, 178, 180, 182, 188, 190, 192, 203, 212, 223, 225, 230, 232

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

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

EXAMPLE

a(1)=3 because prime(3-1)=3 and prime(3+1)=7 are not of the form 6k-1.

MATHEMATICA

pnQ[n_]:=NoneTrue[{Prime[n-1], Prime[n+1]}, IntegerQ[(#+1)/6]&]; Select[ Range[ 2, 300], pnQ] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Dec 04 2019 *)

CROSSREFS

Cf. A007528.

Sequence in context: A187872 A180450 A051507 * A347834 A060274 A345130

Adjacent sequences: A173142 A173143 A173144 * A173146 A173147 A173148

KEYWORD

nonn,easy,less

AUTHOR

Juri-Stepan Gerasimov, Feb 11 2010

EXTENSIONS

1 removed, 113 inserted - R. J. Mathar, Mar 09 2010

STATUS

approved