1,2

Even numbers can't appear in this sequence. - Alonso del Arte, Sep 21 2011

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

aheadOnesRLQ[n_Integer] := Module[{digits, len, flag = True, iter = 1, ones = 0, zeros = 0}, digits = Reverse[IntegerDigits[n, 2]]; len = Length[digits]; While[flag && iter < len, If[digits[[iter]] == 1, ones++, zeros++]; flag = ones > zeros; iter++]; flag]; Select[Range[1, 201, 2], aheadOnesRLQ] (* Alonso del Arte, Sep 21 2011 *)

Select[Range[400], Min[Accumulate[Reverse[IntegerDigits[#, 2]/. (0->-1)]]]> 0&] (* Harvey P. Dale, Apr 23 2016 *)

(Haskell)

a036994 n = a036994_list !! (n-1)

a036994_list = filter ((p 0) . a030308_row) [1, 3 ..] where

p ones [] = ones > 0

p ones (0:bs) = ones > 1 && p (ones - 1) bs

p ones (1:bs) = p (ones + 1) bs

-- Reinhard Zumkeller, Aug 01 2013

(Python)

from itertools import count, islice

def A036994_gen(startvalue=0): # generator of terms >= startvalue

for n in count(max(startvalue, 0)):

s = bin(n)[2:]

c, l = 0, len(s)

for i in range(l):

c += int(s[l-i-1])

if 2*c <= i + 1:

break

else:

yield n

A036994_list = list(islice(A036994_gen(), 20)) # Chai Wah Wu, Dec 31 2021

(PARI) ok(x)={if(x<1, return(0)); my(c=logint(x, 2), c0=0, c1=0); for(i=0, c, if(bittest(x, i), c1++, c0++); if(c1<=c0, return(0))); 1} \\ for(n=1, 367, if(ok(n), print1(n, ", "))) - Ruud H.G. van Tol, Sep 14 2022

Cf. A036990, A036991, A036992, A036993.

Cf. A030308.

Sequence in context: A246521 A160785 A095100 * A243115 A380358 A394060

Adjacent sequences: A036991 A036992 A036993 * A036995 A036996 A036997

nonn,easy,base

More terms from Erich Friedman

approved