OFFSET
1,1
REFERENCES
Z. I. Borevich and I. R. Shafarevich, Number Theory. Academic Press, NY, 1966, pp. 425-430 (but there are errors).
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
FORMULA
EXAMPLE
a(6) = 1 because the 6th irregular prime is 131 and 131 mod 10 = 1.
MATHEMATICA
fQ[n_] := Block[{p = n, k = 1}, While[ 2*k <= p - 3 && Mod[ Numerator[ BernoulliB[ 2*k ]], p ] != 0, k++ ]; 2k != p - 1]; Mod[ Select[ Prime[ Range[2, 275]], fQ[ # ] &], 10] (* Robert G. Wilson v, Dec 10 2004 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Pahikkala Jussi, Dec 04 2004
EXTENSIONS
More terms from Robert G. Wilson v, Dec 10 2004
STATUS
approved