OFFSET
0,1
COMMENTS
Sequence is infinite, as a corollary of Dirichlet's theorem: e.g. for each k there are primes p with p-1 divisible by 2^k. - Robert Israel, Jul 09 2018
LINKS
Robert Israel, Table of n, a(n) for n = 0..500
EXAMPLE
Primes 19 and 29 are not members as the prime signature p^2*q is the same as that corresponding to the prime 13 (12, 18 and 28 have the same prime signature).
MAPLE
p:= 1: PS:= {}: Res:= NULL: count:= 0:
while count < 100 do
p:= nextprime(p);
ps:= sort(map(t -> t[2], ifactors(p-1)[2]));
if not member(ps, PS) then
count:= count+1; Res:= Res, p; PS:= PS union {ps}
fi
od:
Res; # Robert Israel, Jul 09 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Sep 11 2003
EXTENSIONS
Edited by Ray Chandler, Sep 14 2003
STATUS
approved