OFFSET
1,1
COMMENTS
The odd primes squared plus 1 and the nonprimes squared minus 1 are the numerators or denominators of an infinite product converging to 1 whose denominators or numerators, conversely, are the squares of said numbers, that is, (p^2+1/p^2)*(q^2-1)/q^2)..., where p is an odd prime and q is a nonprime.
LINKS
Jens Kruse Andersen, Table of n, a(n) for n = 1..10000
PROG
(PARI) lista(nn) = {for (n=3, nn, if (isprime(n), print1(n^2+1, ", "), print1(n^2-1, ", ")); ); } \\ Michel Marcus, Aug 26 2014
(Python)
for n in range(3, 10**3):
..if isprime(n):
....print(n**2+1, end=', ')
..else:
....print(n**2-1, end=', ') # Derek Orr, Sep 19 2014
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Leo Depuydt, Aug 26 2014
EXTENSIONS
More terms from Michel Marcus, Aug 26 2014
STATUS
approved