OFFSET
1,2
LINKS
Donovan Johnson, Table of n, a(n) for n = 1..1000
EXAMPLE
60 is in the sequence because 60 + 30 + 15 + 46 + 23 + 70 + 35 + 106 + 53 + 160 + 80 + 40 + 20 + 10 + 5 + 16 + 8 + 4 + 2 + 1 = 784 = 28^2.
MATHEMATICA
collatz[n_] := NestWhileList[If[EvenQ[#], #/2, 3#+1]&, n, #>1&]; Select[Range[22000], IntegerQ[Sqrt[Total[collatz[#]]]]&]
CROSSREFS
KEYWORD
nonn
AUTHOR
Michel Lagneau, May 18 2013
STATUS
approved