OFFSET
1,1
COMMENTS
Subsequence of A018900. - Chai Wah Wu, Apr 07 2025
LINKS
Chai Wah Wu, Table of n, a(n) for n = 1..10000 (terms 1..99 from Gil Broussard)
EXAMPLE
a(1) = 5 = 101_2.
a(2) = 9 = 1001_2.
a(3) = 10 = 1010_2.
a(100) = 33024 = 1000000100000000_2.
MATHEMATICA
Select[Range[2500], DigitCount[#, 2, 1]==2&&SequenceCount[IntegerDigits[#, 2], {1, 1}]==0&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Oct 25 2017 *)
PROG
(Python)
from math import isqrt, comb
def A136318(n): return (1<<(m:=isqrt(n<<3)+1>>1)+1)+(1<<n-1-comb(m, 2)) # Chai Wah Wu, Apr 07 2025
CROSSREFS
KEYWORD
nonn,easy,base
AUTHOR
Gil Broussard, Mar 24 2008
STATUS
approved