OFFSET
1,1
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..500
EXAMPLE
a(9) = 5039: lcm(1..9) = 2520; 2519 is not a prime but 2*2520 - 1 = 5039 is a prime.
MATHEMATICA
spf[n_]:=Module[{c=LCM@@Range[n], k=1}, While[!PrimeQ[k*c-1], k++]; k*c-1]; Array[spf, 30] (* Harvey P. Dale, Jan 15 2022 *)
PROG
(PARI) a(n) = {my(lcmn = lcm(vector(n, k, k)), k = 1); while(!isprime(p = k*lcmn-1), k++); p; } \\ Michel Marcus, Mar 15 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Amarnath Murthy and Meenakshi Srikanth (menakan_s(AT)yahoo.com), Jun 15 2003
EXTENSIONS
Corrected and extended by Vladeta Jovovic, Jun 16 2003
STATUS
approved