OFFSET
1,1
COMMENTS
Conjecture: a(n) > 0 for all n.
a(n) is currently unknown for n = 121, 124, 143, 162, 171, 172, 185, 188, 197, 215, ..., for which we have n * a(n) > 130000.
a(121) = (A117545(2048))/11 and they are both currently unknown.
a(130) = 917, a(144) = 820, a(164) = 720, a(201) = 606. - Max Alekseyev, Dec 04 2024
LINKS
Eric Chen, Table of n, a(n) for n = 1..120
Eric Chen, Table of n, a(n) for n = 1..300 status
MATHEMATICA
Table[k=1; while[!PrimeQ[Cyclotomic[n*k, 2]], k++]; k, {n, 150}]
PROG
(PARI) a(n) = {k = 1; while (!isprime(polcyclo(k*n, 2)), k++); k; } \\ Michel Marcus, Jan 18 2015
CROSSREFS
KEYWORD
nonn
AUTHOR
Eric Chen, Jan 18 2015
STATUS
approved