A247280 - OEIS

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A247280

Numbers n for which A242720(n) = prime(n)*(prime(n)+4)+3.

4, 6, 8, 19, 50, 59, 63, 65, 78, 85, 93, 112, 117, 143, 237, 254, 264, 276, 287, 303, 333, 371, 380, 425, 435, 440, 447, 459, 483, 485, 537, 612, 614, 659, 731, 851, 877, 920, 983, 994, 1025, 1080, 1096, 1182, 1358, 1380, 1468, 1476, 1481, 1582, 1628, 1690

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OFFSET

1,1

COMMENTS

prime(n)*(prime(n)+4) + 3, such that prime(n)+4 and prime(n)*(prime(n)+4)+2 are primes, is the second minimal possible value of A242720(n) after (prime(n)+1)^2 + 2, n>=3 (cf. A246824).

LINKS

Table of n, a(n) for n=1..52.

CROSSREFS

Cf. A242719, A242720, A242847, A245363, A246748, A246824, A247011.

Sequence in context: A210459 A346868 A279896 * A226237 A114315 A058238

Adjacent sequences: A247277 A247278 A247279 * A247281 A247282 A247283

KEYWORD

nonn

AUTHOR

Vladimir Shevelev, Sep 11 2014

EXTENSIONS

More terms from Peter J. C. Moses, Sep 11 2014

STATUS

approved