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A030472 Primes which when concatenated with next 3 primes are also prime. 2
2, 67, 83, 139, 149, 383, 503, 557, 577, 587, 601, 613, 727, 937, 1181, 1259, 1451, 1453, 1489, 1531, 1621, 1657, 1831, 1879, 1907, 2269, 2441, 2531, 2897, 3191, 3709, 3779, 4057, 4153, 4373, 4603, 4871, 5197, 5233, 5261, 5279, 5417, 5711 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Paolo P. Lava, Table of n, a(n) for n = 1..1500

EXAMPLE

concat(2, 3, 5, 7) = 2357 is prime. - Paolo P. Lava, Jan 25 2017

MAPLE

with(numtheory): P:=proc(q) local a, b, c, d, f, g, n; for n from 1 to q do a:=ithprime(n); b:=nextprime(a); c:=nextprime(b); d:=nextprime(c); f:=c*10^(ilog10(d)+1)+d; g:=b*10^(ilog10(f)+1)+f;

if isprime(a*10^(ilog10(g)+1)+g) then a; fi;

od; end: seq(P(k), k=1..600); # Paolo P. Lava, Jan 25 2017

CROSSREFS

Cf. A000040.

Sequence in context: A131604 A139861 A065721 * A106998 A275114 A217599

Adjacent sequences:  A030469 A030470 A030471 * A030473 A030474 A030475

KEYWORD

nonn,base

AUTHOR

Patrick De Geest

STATUS

approved

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Last modified July 12 05:35 EDT 2020. Contains 335658 sequences. (Running on oeis4.)