-1986

Appears in sequences

• a(1) = 0, a(2) = -2; for n > 2, a(n) + a(n-2) - a(n-3) - a(n-5) - ... - a(n-p) = (-1)^(n+1)*n if n is prime, otherwise = 0, where p = largest prime < n.at n=50A002120
• Calendar Problem #27, April 2012 Mathematics Teacher.at n=1A208646