OFFSET
1,2
COMMENTS
Dinculescu notes that when n^2 or n^3 is a twin rank > 1 (i.e., in A002822), then n is a multiple of 5, resp. 7. It is unknown whether there exist other pairs (a, b) different from (5, 2) and (7, 3) such that n^b => a | n. (Of course (5, 2k) and (7, 3k) and (35, 6k) is a solution for any k.) See A326233 for the terms > 1 divided by 7.
LINKS
A. Dinculescu, Table of n, a(n) for n = 1..14709
A. Dinculescu, On the Numbers that Determine the Distribution of Twin Primes, Surveys in Mathematics and its Applications, 13 (2018), 171-181.
FORMULA
a(n) = 7*A326233(n-1), n >= 2.
PROG
(PARI) select( is(n)=!for(s=1, 2, ispseudoprime(6*n^3+(-1)^s)||return), [1..10^5])
CROSSREFS
KEYWORD
nonn
AUTHOR
M. F. Hasler and Antonie Dinculescu, Jun 14 2019
STATUS
approved