OFFSET
1,2
COMMENTS
See A191203.
LINKS
Ivan Neretin, Table of n, a(n) for n = 1..10000
EXAMPLE
1 -> 3 -> 6,7 -> 13,15,21,28 ->
MATHEMATICA
g=11; Union[Flatten[NestList[{1+2#, (#^2+#)/2} &, 1, g]]]
(* A191290; use g>9 to get all of first 60 terms *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, May 29 2011
STATUS
approved