A212440 Numbers with even curling numbers of their binary representations, cf. A181935.

3, 4, 10, 11, 12, 15, 16, 19, 20, 21, 26, 27, 28, 35, 36, 37, 43, 44, 45, 47, 48, 51, 52, 53, 54, 58, 59, 60, 63, 64, 67, 68, 69, 73, 74, 75, 76, 79, 80, 82, 83, 84, 90, 91, 92, 99, 100, 101, 107, 108, 109, 111, 112, 115, 116, 117, 118, 122, 123, 124, 131

Offset: 1

Author

Reinhard Zumkeller, May 17 2012

Keywords

• nonn
• base

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
• Index entries for sequences related to binary expansion of n.

Crossrefs

Complement of A212441.

Cf. A181935, A212412.

Programs

Haskell

a212440 n = a212440_list !! (n-1)
a212440_list = filter (even . a181935) [0..]

Mathematica

f[n_, e_] := Module[{d = IntegerDigits[n, 2^e]}, Length[Split[d][[-1]]] - If[SameQ @@ d && Mod[n, 2^e] < 2^(e - 1), 1, 0]]; q[n_] := EvenQ[Max[Table[f[n, e], {e, Range[Max[1, Floor[Log2[n]]]]}]]]; q[0] = False; Select[Range[0, 150], q] (* Amiram Eldar, Apr 08 2025 *)

Formula

A212412(a(n)) = 0.