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A172056 Primes p such that 2*p+-1 and 2*p+-3 are all composites. 1
59, 61, 103, 109, 149, 151, 163, 257, 313, 389, 401, 449, 479, 541, 569, 571, 673, 677, 709, 733, 769, 821, 823, 839, 857, 883, 919, 947, 971, 983, 1061, 1087, 1093, 1097, 1129, 1151, 1163, 1181, 1249, 1283, 1301, 1319, 1321, 1381, 1433, 1489, 1493, 1549 (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)=59 because 2*59-1=117, 2*59+1=119, 2*59-3=115, 2*59+3=121 are all composites.

MATHEMATICA

okQ[n_]:=Union[PrimeQ[{2n+1, 2n-1, 2n+3, 2n-3}]]=={False}; Select[Prime[Range[250]], okQ] [From Harvey P. Dale, Feb 07 2010]

Select[Prime[Range[300]], AllTrue[2#+{1, 3, -1, -3}, CompositeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Feb 20 2015 *)

CROSSREFS

Cf. A000040, A002808, A068497.

Sequence in context: A172462 A042739 A172256 * A032648 A235808 A290170

Adjacent sequences:  A172053 A172054 A172055 * A172057 A172058 A172059

KEYWORD

nonn

AUTHOR

Juri-Stepan Gerasimov, Jan 24 2010

EXTENSIONS

Corrected and extended by Harvey P. Dale, Feb 07 2010

STATUS

approved

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Last modified June 6 10:57 EDT 2020. Contains 334837 sequences. (Running on oeis4.)