OFFSET
1,1
COMMENTS
By the construction of A182481, every term is lesser of twin primes.
Every lesser more than 3 of twin primes appears in the sequence.
Number m=(a(n)+1)/6 is the place of the last appearance of a(n); m is multiple of all previous places of the appearance of a(n), if they exist.
In particular, a(n) appears only once, if (a(n)+1)/6 is 1 or prime (in this case n is 1 or prime and A182481(n)=1). Conversely is not true. For example, a(10)=59 appears only once, although 10 is not prime.
LINKS
Ray Chandler, Table of n, a(n) for n = 1..10000
EXAMPLE
All places where 71 appears are 4,6,12. "Thus" 12 is multiple of 4 and 6.
Since (101+1)/6=17 is prime, then 101 appears only once.
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Shevelev, May 01 2012
STATUS
approved