%I #15 Oct 06 2018 11:46:50

%S 3,5,7,19,23,29,47,61,97,181,233,307,401,887,1021,1087,1361,1481,2053,

%T 2293,5407,5857,11059,14281,27277,27803,36497

%N Primes p such that lcm(1,2,3,...,p-2,p-1,p) - 1 is prime.

%C a(28) > 42000. - _Daniel Suteu_, Oct 06 2018

%F A057825 INTERSECT A000040. - _R. J. Mathar_, Jan 14 2009

%e 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

%p 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

%Y Cf. A056604, A154525, A154526.

%K nonn

%O 1,1

%A _Lekraj Beedassy_, Jan 11 2009

%E a(8)-a(17) from _Ray Chandler_, Jan 16 2009

%E a(18)-a(22) from _Emeric Deutsch_, Jan 16 2009

%E a(23)-a(27) from _Daniel Suteu_, Oct 06 2018