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A032619 Numbers n such that n concatenated with n + 4 is a prime. 2
3, 5, 17, 27, 35, 39, 45, 47, 63, 65, 83, 93, 99, 113, 123, 147, 149, 173, 185, 203, 209, 213, 219, 227, 239, 249, 255, 263, 267, 285, 287, 303, 309, 317, 327, 329, 333, 363, 365, 399, 413, 419, 423, 435, 447, 459, 465, 467, 473, 489, 497, 509, 515, 519 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

MAPLE

filter:= n -> isprime(n*(10^(1+ilog10(n+4))+1)+4):

select(filter, [seq(i, i=1..1000, 2)]); # Robert Israel, Nov 14 2019

CROSSREFS

Cf. A032609.

Sequence in context: A281622 A256439 A256444 * A193066 A193070 A030077

Adjacent sequences:  A032616 A032617 A032618 * A032620 A032621 A032622

KEYWORD

nonn,base

AUTHOR

Patrick De Geest, May 15 1998

STATUS

approved

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Last modified June 6 04:15 EDT 2020. Contains 334859 sequences. (Running on oeis4.)