|
|
A083554
|
|
Least common multiple of prime(n+1)-1 and prime(n)-1.
|
|
3
|
|
|
2, 4, 12, 30, 60, 48, 144, 198, 308, 420, 180, 360, 840, 966, 1196, 1508, 1740, 660, 2310, 2520, 936, 3198, 3608, 1056, 2400, 5100, 5406, 5724, 3024, 1008, 8190, 8840, 9384, 10212, 11100, 3900, 4212, 13446, 14276, 15308, 16020, 3420, 18240, 9408
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
LINKS
|
|
|
FORMULA
|
|
|
EXAMPLE
|
n=25: a(25) = lcm(97-1, 101-1) = lcm(96,100) = 2400.
|
|
MATHEMATICA
|
f[x_] := Prime[x]-1; Table[LCM[f[w+1], f[w]], {w, 1, 128}]
|
|
PROG
|
(PARI) a(n) = lcm(prime(n+1)-1, prime(n)-1); \\ Michel Marcus, Mar 15 2018
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|