The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A224183 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A224183

Number of halving and tripling steps to reach the last number of the cycle in the Collatz (3x+1) problem for the negative integers (the initial term is not counted).
(history; published version)

#18 by OEIS Server at Sun Jan 24 11:16:24 EST 2021

LINKS

Michel Lagneau, <a href="/A224183/b224183_1.txt">Table of n, a(n) for n = 1..10000</a>

#17 by Alois P. Heinz at Sun Jan 24 11:16:24 EST 2021

STATUS

proposed

approved

Discussion

Sun Jan 24

11:16

OEIS Server: Installed new b-file as b224183.txt.  Old b-file is now b224183_1.txt.

#16 by Pontus von Brömssen at Sun Jan 24 10:48:31 EST 2021

STATUS

editing

proposed

Discussion

Sun Jan 24

11:16

Alois P. Heinz: ok, thanks

#15 by Pontus von Brömssen at Sun Jan 24 10:48:09 EST 2021

LINKS

Pontus von Brömssen, Michel Lagneau, <a href="/A224183/b224183_1.txt">Table of n, a(n) for n = 1..10000</a>

Discussion

Sun Jan 24

10:48

Pontus von Brömssen: Changed a(1) in b-file.

#14 by Pontus von Brömssen at Sun Jan 24 10:46:53 EST 2021

LINKS

Michel Lagneau, Pontus von Brömssen, <a href="/A224183/b224183_1.txt">Table of n, a(n) for n = 1..10000</a>

STATUS

approved

editing

#13 by Alois P. Heinz at Sun Jan 24 10:29:39 EST 2021

STATUS

proposed

approved

#12 by Alois P. Heinz at Sun Jan 24 09:30:42 EST 2021

STATUS

editing

proposed

#11 by Alois P. Heinz at Sun Jan 24 09:30:35 EST 2021

MAPLE

printf(`%d, `, 01): for n from -2 by -1 to -100 do:x:=n:lst:={n}:for it from 1 to 100 do:if irem(x, 2)=0 then x := x/2: lst:=lst union{x} :else x := 3*x+1: lst:=lst union{x}fi:od:d:=nops(lst): printf(`%d, `, d-1): od:

STATUS

proposed

editing

#10 by Pontus von Brömssen at Sun Jan 24 09:15:17 EST 2021

STATUS

editing

proposed

#9 by Pontus von Brömssen at Sun Jan 24 09:13:11 EST 2021

MATHEMATICA

Collatz[n_] := NestWhileList[If[EvenQ[#], #/2, 3 # + 1] &, n, UnsameQ, All]; Join[{0}, Table[s = Collatz[-n]; len = Length[s] - 2; If[s[[-1]] == 2, len = len - 1]; len, {n, 2, 1, 100}]]

Discussion

Sun Jan 24

09:14

Pontus von Brömssen: I'll fix the b-file and make the corresponding change to A224166 if this gets approved.