OFFSET
1,1
COMMENTS
All terms have digital root equal to 9.
LINKS
Odimar Fabeny, Table of n, a(n) for n = 1..10000
MATHEMATICA
Differences[Select[Range[13, 3000, 18], CompositeQ]] (* Harvey P. Dale, Aug 21 2024 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Odimar Fabeny, Sep 26 2014
STATUS
approved