OFFSET
1,1
COMMENTS
a(n) is a "lesser of a 4-twin" prime whose distance to the next twin is 6n.
Both the smallest distance (A052380) and its increment for 4-twins is 6.
FORMULA
The prime a(n)=p is the first which determines a prime quadruple [p, p+4, p+6n, p+6n+4] and difference pattern of [4, 6n-4, 4].
EXAMPLE
a(1)=7 gives [7,11,7+6=13,17] with no primes between 11 and 13.
a(5)=163 specifies [163,167,163+30=191,193] with 4 primes between 167 and 193.
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Mar 07 2000
STATUS
approved