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A331831
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Numbers k such that k and k + 1 are both negabinary odious numbers.
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2
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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
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OFFSET
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1,1
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LINKS
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EXAMPLE
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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.
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MATHEMATICA
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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
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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