

A328012


Numbers whose binary representations start and end with 1 and contain an even number of zeros between.


1



1, 3, 7, 9, 15, 19, 21, 25, 31, 33, 39, 43, 45, 51, 53, 57, 63, 67, 69, 73, 79, 81, 87, 91, 93, 97, 103, 107, 109, 115, 117, 121, 127, 129, 135, 139, 141, 147, 149, 153, 159, 163, 165, 169, 175, 177, 183, 187, 189, 195, 197, 201, 207, 209, 215, 219, 221, 225
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OFFSET

1,2


COMMENTS

Odd members of A059010.  Robert Israel, Nov 30 2019


LINKS

Jonathan Frech, Table of n, a(n) for n = 1..10000


MAPLE

q:= n> (l> l[1]=1 and add(1i, i=l)::even)(Bits[Split](n)):
select(q, [$1..300])[]; # Alois P. Heinz, Oct 04 2019


MATHEMATICA

{1}~Join~Select[Range[3, 225, 2], EvenQ@ DigitCount[#, 2, 0] &] (* Michael De Vlieger, Oct 05 2019 *)


PROG

(PARI) ok(n)={n%2 && hammingweight((2<<logint(n, 2))  1  n)%2==0} \\ Andrew Howroyd, Oct 01 2019
(Python)
n, a = 0, 1
while n < 58:
aa, k = a, 0
while aa > 0:
d, aa = aa%2, aa//2
if d == 0:
k = k+1
if k%2 == 0:
n = n+1
print(n, a)
a = a+2 # A.H.M. Smeets, Oct 04 2019


CROSSREFS

Cf. A023416, A059010.
Sequence in context: A187108 A026175 A026139 * A292911 A119681 A197625
Adjacent sequences: A328009 A328010 A328011 * A328013 A328014 A328015


KEYWORD

nonn,base


AUTHOR

Justin Clifton, Oct 01 2019


EXTENSIONS

More terms from Alois P. Heinz, Oct 04 2019


STATUS

approved



