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A154524 Primes p such that lcm(1,2,3,...,p-2,p-1,p) - 1 is prime. 2
3, 5, 7, 19, 23, 29, 47, 61, 97, 181, 233, 307, 401, 887, 1021, 1087, 1361, 1481, 2053, 2293, 5407, 5857 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..22.

FORMULA

A057825 INTERSECT A000040. - R. J. Mathar, Jan 14 2009

EXAMPLE

7 is in the sequence because it is prime and also lcm(1,2,3,4,5,6,7)-1 = 420-1 = 419 is prime. - Emeric Deutsch, Jan 16 2009

MAPLE

P := proc(n) options operator, arrow: ilcm(seq(j, j = 1 .. n)) end proc: a := proc(n) if isprime(n) and isprime(P(n)-1) then n else end if end proc: seq(a(n), n = 1 .. 3000); # Emeric Deutsch, Jan 16 2009

CROSSREFS

Cf. A056604, A154525, A154526.

Sequence in context: A002261 A263257 A261456 * A184805 A079131 A179687

Adjacent sequences:  A154521 A154522 A154523 * A154525 A154526 A154527

KEYWORD

nonn

AUTHOR

Lekraj Beedassy, Jan 11 2009

EXTENSIONS

a(8)-a(27) from Ray Chandler, Jan 16 2009

More terms from Emeric Deutsch, Jan 16 2009

STATUS

approved

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Last modified September 22 11:00 EDT 2018. Contains 315270 sequences. (Running on oeis4.)