A384096 a(n) = 2*n - A080776(n).

0, 2, 3, 6, 7, 8, 11, 14, 15, 16, 17, 18, 21, 24, 27, 30, 31, 32, 33, 34, 35, 36, 37, 38, 41, 44, 47, 50, 53, 56, 59, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 81, 84, 87, 90, 93, 96, 99, 102, 105, 108, 111, 114, 117, 120, 123, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140

Offset

0,2

Links

Table of n, a(n) for n=0..77.

Formula

a(2k+1) = 2 + 2*a(k), a(2k+2) = 2 + a(k) + a(k+1), for k > 0.

a(n) is a multiple of n iff n = 2^m-1 for some m >= 0.

Maple

a:= n-> 2*n-(h-> min(n+1-h, 2*h-n-1))(2^ilog2(n+1)):
seq(a(n), n=0..77);  # Alois P. Heinz, Oct 27 2025

Prog

(PARI) apply( {a(n)=2*n-A080776(n)}, [0..99])
(Python)
def A384096(n): return max(n-1+(m:=1<<(n+1).bit_length()-1), 3*n-(m<<1)+1) # Chai Wah Wu, Oct 31 2025

Crossrefs

Cf. A080776.

Sequence in context: A097757 A304028 A155152 * A098740 A116046 A069579

Adjacent sequences: A384093 A384094 A384095 * A384097 A384098 A384099

Keyword

nonn,easy

Author

M. F. Hasler, Oct 27 2025

Status

approved