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A166458 10n - (-1)^n is prime. 1
1, 2, 3, 6, 7, 8, 13, 14, 15, 18, 19, 20, 21, 24, 25, 27, 31, 33, 36, 38, 42, 43, 44, 48, 49, 50, 57, 60, 62, 63, 66, 69, 72, 74, 75, 81, 84, 86, 91, 92, 97, 99, 102, 103, 104, 105, 109, 115, 117, 123, 126, 128, 129, 132, 140, 144, 145, 146, 147, 150, 151, 153, 156, 157 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..10000

EXAMPLE

if 1*10-(-1)^1=11=prime, then a(1)=1; if 2*10-(-1)^2=19=prime, then a(2)=2; if 3*10-(-1)^3=31=prime, then a(3)=3; if 6*10-(-1)^6=59=prime, then a(4)=6.

MATHEMATICA

Select[If[PrimeQ[10*# - (-1)^#], #] & /@ Range[6!], IntegerQ] (* G. C. Greubel, May 15 2016 *)

CROSSREFS

Cf. A122869.

Sequence in context: A189137 A230548 A294375 * A189013 A242940 A127330

Adjacent sequences:  A166455 A166456 A166457 * A166459 A166460 A166461

KEYWORD

nonn,easy

AUTHOR

Juri-Stepan Gerasimov, Oct 14 2009

EXTENSIONS

Corrected (77 removed) by R. J. Mathar, May 21 2010

STATUS

approved

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Last modified July 21 04:40 EDT 2019. Contains 325189 sequences. (Running on oeis4.)