OFFSET
1,1
COMMENTS
Minimal value 12 is for n = 3, 6, 22, 43, 90, 123, 125, 135, 144, 147, 201, 255, 276, 287, 310, 338, 350. - Zak Seidov, Jun 12 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Mar 06 2000
STATUS
approved