Print the Super Collatz numbers
Python 2, 104 bytes
c=lambda x:x>1and 1+c([x/2,x*3+1][x%2])
lambda n:[1]+[x for x in range(2,n)if c(x)>max(map(c,range(x)))]
c
is a helper function that calculates the Collatz distance for a given integer. The unnamed lambda is the main function, which computes the super Collatz numbers up to (but not including) the input.
Dyalog APL, 41 bytes
(∪⊢⍳⌈\)≢∘{1=⍵:⍬⋄2|⊃⌽⍵:⍵,∇1+3×⍵⋄⍵,∇⍵÷2}¨∘⍳
An unnamed function. Name or parenthesize to apply.
Test cases:
((∪⊢⍳⌈\)≢∘{1=⍵:⍬ ⋄ 2|⊃⌽⍵:⍵,∇ 1+3×⍵ ⋄ ⍵,∇ ⍵÷2}¨∘⍳)¨4 50 10000
┌─────┬────────────────────┬───────────────────────────────────────────────────────────────────────────────────────────┐
│1 2 3│1 2 3 6 7 9 18 25 27│1 2 3 6 7 9 18 25 27 54 73 97 129 171 231 313 327 649 703 871 1161 2223 2463 2919 3711 6171│
└─────┴────────────────────┴───────────────────────────────────────────────────────────────────────────────────────────┘
0 results in undefined behaviour.