OFFSET
1,2
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 1..1000
PROG
(Haskell)
a170803 n = a170803_list !! (n-1)
a170803_list = scanl1 (+) a006899_list -- Reinhard Zumkeller, Oct 09 2013
(Python)
from sympy import integer_log
def A170803(n): return ((a:=1<<k+1)<<1)-2+(3**integer_log(a, 3)[0]*3-1>>1) if 6**(k:=integer_log(m:=3**(n-1), 6)[0])<<1<m else ((a:=3**integer_log(1<<n, 6)[0])*3-1>>1)+(1<<a.bit_length())-2 # Chai Wah Wu, Feb 05 2025
CROSSREFS
KEYWORD
nonn,changed
AUTHOR
N. J. A. Sloane, Dec 12 2009
STATUS
approved