OFFSET
1,1
COMMENTS
Phi(3,k) = k^2 + k + 1 and Phi(6,k) = k^2 - k + 1.
Interesting scatter plot.
The terms correspond to the new primes of A081257 in the order of their appearance for n>1 and when A081257(m)>m. - Bill McEachen, Oct 13 2022
LINKS
Robert Price, Table of n, a(n) for n = 1..733
Bernhard Helmes, Prime sieving on the polynomial f(n)=n^2+n+1.
MATHEMATICA
prim = {}; Do[prim = Join[prim, Complement[First /@ FactorInteger[Cyclotomic[6, k]], prim]], {k, 1000}]; prim
PROG
(PARI) lista(nn) = {vs = []; for (n=1, nn, vp = factor(polcyclo(6, n))[, 1]; for (i=1, #vp, if (!vecsearch(vs, vp[i]), print1(vp[i], ", "); vs = vecsort(concat(vs, vp[i]), , 8); ); ); ); } \\ Michel Marcus, Mar 20 2015
CROSSREFS
KEYWORD
nonn,look
AUTHOR
Robert Price, Mar 16 2015
STATUS
approved