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A216299 Numbers k such that 10k+1 is composite but 10k+3, 10k+7, 10k+9 are all prime. 1
22, 61, 85, 142, 166, 169, 178, 199, 268, 316, 415, 451, 478, 541, 682, 775, 787, 862, 1045, 1111, 1237, 1387, 1618, 1720, 1738, 2014, 2035, 2074, 2131, 2215, 2305, 2362, 2410, 2710, 2773, 2938, 3013, 3055, 3271, 3334, 3361, 3412, 3652, 4012, 4042, 4069 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

V. Raman, Table of n, a(n) for n = 1..10000

FORMULA

a(n) >> n log^3 n. - Charles R Greathouse IV, Sep 07 2012

MATHEMATICA

t = {}; Do[ps = Select[Range[10*n, 10*n + 9], PrimeQ]; If[ps == {10*n + 3, 10*n + 7, 10*n + 9}, AppendTo[t, n]], {n, 0, 4978}]; t (* T. D. Noe, Sep 03 2012 *)

Select[Range[4100], CompositeQ[10#+1]&&AllTrue[10#+{3, 7, 9}, PrimeQ]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Sep 14 2019 *)

PROG

(MAGMA) [k:k in [1..4100]| not IsPrime(10*k+1) and forall{m:m in [3, 7, 9]| IsPrime(10*k+m)}]; // Marius A. Burtea, Feb 02 2020

CROSSREFS

Cf. A032352, A007811, A078494.

Sequence in context: A044124 A044505 A156797 * A255431 A221595 A051874

Adjacent sequences:  A216296 A216297 A216298 * A216300 A216301 A216302

KEYWORD

nonn

AUTHOR

V. Raman, Sep 03 2012

STATUS

approved

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Last modified May 22 22:13 EDT 2022. Contains 353959 sequences. (Running on oeis4.)