OFFSET
1,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
Richard K. Guy, Letter to N. J. A. Sloane, 1987.
FORMULA
a(n) = A006093(n)^2. - Wesley Ivan Hurt, Mar 27 2014
Sum_{n>=1} 1/a(n) = A086242. - Amiram Eldar, Nov 09 2020
From Amiram Eldar, Jan 23 2021: (Start)
Product_{n>=1} (1 + 1/a(n)) = A065485.
Product_{n>=2} (1 - 1/a(n)) = A005597. (End)
MAPLE
MATHEMATICA
Table[(Prime[n] - 1)^2, {n, 40}] (* Vincenzo Librandi, Mar 27 2014 *)
PROG
(Magma) [(p-1)^2: p in PrimesUpTo(200)]; // Vincenzo Librandi, Mar 27 2014
(PARI) a(n) = (prime(n) - 1)^2; \\ Michel Marcus, Nov 09 2020
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Scorpion(AT)aol.com
STATUS
approved