OFFSET
1,4
LINKS
Eric Weisstein's World of Mathematics, Symmetric Graph
FORMULA
a(n) = Sum{d|n, d<n} A133181(d). - Charlie Neder, Apr 24 2019
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Eric W. Weisstein, Aug 19 2003
EXTENSIONS
Corrected and extended by David Wasserman, Feb 14 2006
a(12)-a(31) from Charlie Neder, Apr 24 2019
STATUS
approved