OFFSET
1,1
COMMENTS
REFERENCES
R. F. Lukes, C. D. Patterson and H. C. Williams, Numerical sieving devices: their history and some applications. Nieuw Arch. Wisk. (4) 13 (1995), no. 1, 113-139. Math. Rev. 96m:11082
LINKS
G. W. Fung and H. C. Williams, Quadratic polynomials with high density of primes, Mathematics of Computation, Vol. 55, 1990.
C. Rivera, www.primepuzzles.net, Conjecture 17
EXAMPLE
k^2 + k + 2 takes the values 2, 4, 8, 14, ... for k = 0,1,2,...; the smallest prime divisor of these numbers is 2, so f(2) = 2.
MATHEMATICA
(* This program is not convenient beyond a(24) *) a[1] = 2; a[2] = 3; a[n_] := For[d = 1, True, d = d+2, If[And @@ (# == -1 & /@ Table[JacobiSymbol[1 - 4d, Prime[k]], {k, 2, n}]) && JacobiSymbol[1 - 4d, Prime[n+1]] != -1, Return[d]]]; Table[Print[an = a[n]]; an, {n, 1, 24}] (* Jean-François Alcover, Oct 14 2013, after T. D. Noe *)
CROSSREFS
KEYWORD
hard,nice,nonn
AUTHOR
Luis Rodriguez-Torres (ludovicusmagister(AT)yahoo.com), Apr 03 2001
EXTENSIONS
Corrected by T. D. Noe, Apr 19 2004
STATUS
approved