OFFSET
1,2
COMMENTS
The smallest positive number such that A024629(a(n)) has n digits, per page 9 of the Tanton reference in Links. - Glen Whitney, Sep 17 2017
REFERENCES
Wolfram, S. A New Kind of Science. Champaign, IL: Wolfram Media, 2002, p. 123.
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 1..1000
B. Chen, R. Chen, J. Guo, S. Lee et al., On Base 3/2 and its Sequences, arXiv:1808.04304 [math.NT], 2018.
James Tanton, Exploding Dots, Chapter 9
Eric Weisstein's World of Mathematics, Wolfram Sequences
FORMULA
For n > 1, a(n) = 3*A061419(n) = 3*floor(K*(3/2)^n) where K=1.08151366859... - Benoit Cloitre, Aug 18 2002
a(n) = 3*ceiling(a(n-1)/2). - Benoit Cloitre, Apr 25 2003
a(n+1) = a(n) + A081848(n), for n > 1. - Reinhard Zumkeller, Sep 05 2014
MAPLE
A070885 := proc(n)
option remember;
if n = 1 then
return 1;
elif type(procname(n-1), 'even') then
procname(n-1) ;
else
procname(n-1)+1 ;
end if;
%*3/2 ;
end proc:
seq(A070885(n), n=1..80) ; # R. J. Mathar, Jun 18 2018
MATHEMATICA
NestList[If[EvenQ[#], 3/2 #, 3/2 (#+1)]&, 1, 40] (* Harvey P. Dale, May 18 2018 *)
PROG
(Haskell)
a070885 n = a070885_list !! (n-1)
a070885_list = 1 : map (flip (*) 3 . flip div 2 . (+ 1)) a070885_list
-- Reinhard Zumkeller, Sep 05 2014
(Python)
from itertools import islice
def A070885_gen(): # generator of terms
a = 1
while True:
yield a
a += (a+1>>1)+(a&1)
CROSSREFS
KEYWORD
nonn
AUTHOR
Eric W. Weisstein, May 14 2002
STATUS
approved