login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A285098 Row sums of irregular triangle A070168. 2

%I

%S 1,3,23,7,20,29,124,15,147,30,117,41,63,138,296,31,106,165,231,50,84,

%T 139,281,65,294,89,40616,166,212,326,40486,63,377,140,258,201,259,269,

%U 986,90,40589,126,588,183,253,327,40455,113,382,344,514,141,223,40670,41000,222

%N Row sums of irregular triangle A070168.

%C a(n) is the sum of numbers in trajectory of Terras-modified Collatz problem with first number n.

%H Indranil Ghosh, <a href="/A285098/b285098.txt">Table of n, a(n) for n = 1..10000</a>

%e The 5th row of irregular triangle A070168 is [5, 8, 4, 2, 1] whose sum is 20. a(5) = 5 + 8 + 4 + 2 + 1 = 20.

%t a[n_]:=If[n<2, 1, If[OddQ[n], (3n + 1)/2, n/2]]; Table[-1 + Plus @@ FixedPointList[a, n], {n, 100}]

%o (Python)

%o def a(n):

%o if n==1: return 1

%o l=[n, ]

%o while True:

%o if n%2==0: n/=2

%o else: n = (3*n + 1)/2

%o l+=[n, ]

%o if n<2: break

%o return sum(l)

%o print [a(n) for n in range(1, 101)]

%Y Cf. A033493, A070168.

%K nonn

%O 1,2

%A _Indranil Ghosh_, Apr 17 2017

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified February 25 08:33 EST 2021. Contains 341606 sequences. (Running on oeis4.)