OFFSET
1,3
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
FORMULA
a(1) = 0, a(2) = 1, a(3) = 2, a(4) = 3, a(2^(m+1)+2^m+k+2) = 2^(m+2) + k, m >= 0, 0 <= k < (2^(m+1)+2^m). - Yosu Yurramendi, Aug 08 2016
From Robert Israel, Aug 08 2016: (Start)
For n >= 5, a(2n-2) = 2 a(n) and a(2n-1) = 2 a(n)+1.
G.f. g(x) satisfies g(x) - (2/x + 2/x^2)*g(x^2) = -x^2 - x^4 - x^6 + x^9/(1-x^2). (End)
MAPLE
f:= proc(n) option remember;
if n < 8 then n-1
else 2*procname(floor((n+2)/2))+(n mod 2)
fi
end proc:
map(f, [$1..100]); # Robert Israel, Aug 08 2016
MATHEMATICA
w = {1, 1, 1}; Select[Range[0, 83], If[# < 2^(Length@ w - 1), True, Take[IntegerDigits[#, 2], Length@ w] != w] &] (* Michael De Vlieger, Aug 08 2016 *)
PROG
(Haskell)
a004765 n = a004765_list !! n
a004765_list = filter f [0..] where
f x | x <= 8 = x /= 7
| otherwise = f (x `div` 2)
-- Reinhard Zumkeller, Jun 03 2012
CROSSREFS
KEYWORD
nonn,easy,base
AUTHOR
STATUS
approved