OFFSET
1,1
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
MATHEMATICA
Total/@Subsets[3^Range[0, 10], {3}]//Union (* Harvey P. Dale, Jul 10 2017 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
EXTENSIONS
Offset corrected by Amiram Eldar, Jul 13 2022
STATUS
approved