OFFSET
1,1
COMMENTS
LINKS
Clark Kimberling, Table of n, a(n) for n = 1..1000
FORMULA
D(prime(k), 3) = P(k+3) - 3*P(k+2) + 3*P(k+1) - P(k), where P(m) = prime(m) for m >= 1.
EXAMPLE
D(prime(1), 3) = 7 - 3*5 + 3*3 - 2 < 0;
D(prime(2), 3) = 11 - 3*7 + 3*5 - 3 > 0, so a(1) = 2;
D(prime(3), 3) = 13 - 3*11 + 3*7 - 5 < 0;
D(prime(4), 3) = 17 - 3*13 + 3*11 - 7 > 0, so a(2) = 4.
MATHEMATICA
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Jun 05 2015
STATUS
approved