A207016 a(1) = 3 , for n > 1 a(n) is the least number greater than a(n-1) such that the Hamming distance D(a(n-1),a(n)) = 3.

3, 4, 9, 14, 18, 21, 24, 31, 39, 41, 46, 50, 53, 56, 63, 79, 83, 84, 89, 94, 102, 104, 111, 115, 116, 121, 126, 158, 166, 168, 175, 179, 180, 185, 190, 206, 210, 213, 216, 223, 231, 233, 238, 242, 245, 248, 255, 319, 335, 339, 340, 345, 350, 358, 360, 367, 371

Offset: 1

Author

Vladimir Shevelev, Feb 14 2012

Keywords

• nonn
• base

Comments

Odious and evil terms are alternating (cf. A000069, A001969).

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..1000 from Alois P. Heinz)

Crossrefs

Cf. A000069, A000225, A001969, A205509, A205510, A205511, A205302, A205649, A205533, A122565, A206852, A206853.

Programs

Mathematica

a[1] = 3; a[n_] := a[n] = Module[{k = a[n - 1], m = a[n-1] + 1}, While[DigitCount[BitXor[k, m], 2, 1] != 3, m++]; m]; Array[a, 100] (* Amiram Eldar, Aug 06 2023 *)

PARI

list(n)=my(v=vector(n));v[1]=3;for(i=2,n,v[i]=v[i-1]; while(hammingweight(bitxor(v[i-1],v[i]++))!=3,));v \\ Charles R Greathouse IV, Mar 26 2013