A083554 - OEIS

%I #16 Apr 09 2021 03:50:37

%S 2,4,12,30,60,48,144,198,308,420,180,360,840,966,1196,1508,1740,660,

%T 2310,2520,936,3198,3608,1056,2400,5100,5406,5724,3024,1008,8190,8840,

%U 9384,10212,11100,3900,4212,13446,14276,15308,16020,3420,18240,9408

%N Least common multiple of prime(n+1)-1 and prime(n)-1.

%H Amiram Eldar, <a href="/A083554/b083554.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = lcm(A006093(n+1), A006093(n)) = lcm(prime(n+1)-1, prime(n)-1).

%e n=25: a(25) = lcm(97-1, 101-1) = lcm(96,100) = 2400.

%t f[x_] := Prime[x]-1; Table[LCM[f[w+1], f[w]], {w, 1, 128}]

%o (PARI) a(n) = lcm(prime(n+1)-1, prime(n)-1); \\ _Michel Marcus_, Mar 15 2018

%Y Cf. A006093, A083538-A083555, A058263.

%K nonn

%O 1,1

%A _Labos Elemer_, May 22 2003