OFFSET
1,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..10000
FORMULA
a(n) = lcm((prime(n+1)+prime(n)), (prime(n+1)-prime(n))).
a(n) = (prime(n+1)^2 - prime(n)^2)/2 for n > 1. - Jon Maiga, Jan 17 2019
EXAMPLE
a(3)=12 because prime(3)=5, prime(4)=7 and lcm(7+5, 7-5) = lcm(12,2) = 12.
MATHEMATICA
LCM[Total[#], #[[2]]-#[[1]]]&/@Partition[Prime[Range[60]], 2, 1] (* Harvey P. Dale, Apr 19 2013 *)
Join[{5}, Table[(Prime[n + 1]^2 - Prime[n]^2)/2, {n, 2, 59}]] (* Jon Maiga, Jan 17 2019 *)
PROG
(PARI) a(n) = my(p = prime(n), q = prime(n+1)); lcm(q+p, q-p); \\ Michel Marcus, Mar 15 2018
CROSSREFS
KEYWORD
nonn,look
AUTHOR
Mitch Cervinka (Mitch.Cervinka(AT)eds.com), Dec 15 2006
STATUS
approved