OFFSET
1,1
COMMENTS
k such that A099905(k) = 1.
Contains primes, squares of odd primes and cubes of primes >= 5.
See A228562 for terms that are neither primes nor prime powers. [Joerg Arndt, Aug 27 2013]
LINKS
McIntosh, R. J. (1995), On the converse of Wolstenholme's theorem, Acta Arithm., LXXI.4 (1995), 381-389.
EXAMPLE
a(3) = 5 because binomial(9, 4) = 126 == 1 (mod 5).
MATHEMATICA
Select[Range[300], Mod[Binomial[2# - 1, # - 1], #] == 1 &] (* Alonso del Arte, May 11 2014 *)
PROG
(PARI) isok(n) = (binomial(2*n-1, n-1) % n) == 1; \\ Michel Marcus, Aug 26 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Franz Vrabec, Mar 26 2008
STATUS
approved