OFFSET
1,1
COMMENTS
Let Phi_k be the k-th cyclotomic polynomial. a(n) is the least integer x such that for each k from 1 to n, Phi_k(x) is prime.
EXAMPLE
a(6)=x=6770610 because Phi_1(x)=x-1, Phi_2(x)=x+1, Phi_3(x)=x^2+x+1, Phi_4(x)=x^2+1, Phi_5(x)=x^4+x^3+x^2+x+1 and Phi_6(x)=x^2-x+1 are all prime.
CROSSREFS
KEYWORD
nonn
AUTHOR
Don Reble, May 15 2002 and Phil Carmody, Aug 09 2002
STATUS
approved