OFFSET
0,1
COMMENTS
A prime number in the arithmetic progression 12n-1 which is not a von Staudt prime number, i.e., 12p <> denominator(B(p-1)/(p-1)), where B(n) is the Bernoulli number.
LINKS
Dana Jacobsen, Table of n, a(n) for n = 0..10883
MAPLE
select(j->(denom(bernoulli(j-1)/(j-1))<>12*j), select(isprime, [seq(12*k-1, k=1..100)]));
MATHEMATICA
Select[ 12*Range[200] - 1, PrimeQ[#] && 12 # != Denominator[ BernoulliB[# - 1]/(# - 1)]& ] ] (* Jean-François Alcover, Jul 29 2013 *)
PROG
(Perl) use ntheory ":all"; forprimes { my $p=$_; say if $_ % 12 == 11 && vecany { $_ > 3 && $_ < $p-1 && is_prime($_+1) } divisors($p-1); } 10000; # Dana Jacobsen, Dec 29 2015
(Perl) use ntheory ":all"; forprimes { say if $_ % 12 == 11 && (bernfrac($_-1))[1] != 6*$_; } 10000; # Dana Jacobsen, Dec 29 2015
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Peter Luschny, Dec 24 2008
STATUS
approved