A008471 - OEIS

A008471

Exactly 3 out of 10m+1, 10m+3, 10m+7, 10m+9 are primes.

4, 7, 13, 22, 31, 43, 46, 61, 64, 85, 88, 103, 106, 109, 130, 142, 145, 160, 166, 169, 178, 199, 238, 268, 271, 316, 367, 376, 391, 400, 409, 415, 421, 451, 472, 478, 493, 523, 541, 544, 547, 550, 574

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OFFSET

1,1

LINKS

V. Raman, Table of n, a(n) for n = 1..10000 (first 1000 terms from Harvey P. Dale)

MATHEMATICA

m3Q[m_]:=Module[{c=10m}, Count[{c+1, c+3, c+7, c+9}, _?PrimeQ]==3]; Select[ Range[ 600], m3Q] (* Harvey P. Dale, Dec 24 2011 *)

PROG

(Magma) [n: n in [1..600] | #PrimesInInterval(10*n+1, 10*n+9) eq 3]; // Bruno Berselli, Sep 04 2012

CROSSREFS

Cf. A007811, A032352, A216292, A216293.

Sequence in context: A147487 A190845 A190805 * A156622 A111314 A316861

Adjacent sequences: A008468 A008469 A008470 * A008472 A008473 A008474

KEYWORD

nonn

AUTHOR

Olivier Gérard

STATUS

approved