A331831 Numbers k such that k and k + 1 are both negabinary odious numbers.

3, 11, 15, 23, 29, 35, 43, 47, 53, 59, 63, 71, 77, 83, 91, 95, 103, 109, 115, 119, 125, 131, 139, 143, 151, 157, 163, 171, 175, 181, 187, 191, 199, 205, 211, 215, 221, 227, 235, 239, 245, 251, 255, 263, 269, 275, 283, 287, 295, 301, 307, 311, 317, 323, 331, 335

Offset: 1

Author

Amiram Eldar, Jan 28 2020

Keywords

• nonn
• base

Examples

			3 is a term since both 3 and 3 + 1 = 4 are negabinary odious numbers (A268273): 3 has 3 digits of 1 in its negabinary representation, 111, 4 has 1 digit of 1 in its negabinary representation, 100, and both 3 and 1 are odd.
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A157971, A268273, A331830.

Programs

Mathematica

negaBinWt[n_] := negaBinWt[n] = If[n==0, 0, negaBinWt[Quotient[n-1, -2]] + Mod[n, 2]]; odNegaBinQ[n_] := OddQ[negaBinWt[n]]; c = 0; k = 1; s = {}; v = Table[-1, {2}]; While[c < 60, If[odNegaBinQ[k], v = Join[Rest[v], {k}]; If[AllTrue[Differences[v], # == 1 &], c++; AppendTo[s, k - 1]]]; k++]; s