OFFSET
1,1
COMMENTS
The author hereby expresses his gratitude to Tony Noe for supplying him with a list of the first irregular primes to 12 million. - Robert G. Wilson v, Mar 31 2005
EXAMPLE
a(1)=37 because neither 31 nor 41, its neighboring primes, are irregular.
a(2)=101 because neither 97 nor 107 are irregular, they being the neighbors of 101 and 103 which are irregular.
a(3)=461 because neither 457 nor 479 are irregular, they being the neighbors of {461, 463, 467} which are all irregular.
MATHEMATICA
fQ[n_] := Block[{ p = Prime[ n ], k = 1}, While[ 2k <= p - 3 && Mod[ Numerator[ BernoulliB[ 2k]], p] != 0, k++ ]; If[ 2k != p - 1, True, False]]; Select[ Range[2, 250], fQ[ # ] &]; s = {}; Do[ If[ fQ[n], AppendTo[s, n]; Print[{n, Prime[n]}]], {n, 1500}]
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Robert G. Wilson v, Mar 31 2005
EXTENSIONS
More terms from Robert G. Wilson v, Mar 31 2005
a(15)-a(18) from Amiram Eldar, Mar 06 2019
STATUS
approved