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A331829
Positive numbers k such that k and k + 1 are both positive negabinary-Niven numbers (A331728) and -k and -(k + 1) are both negative negabinary-Niven numbers (A331819).
1
2, 3, 8, 15, 32, 63, 128, 174, 245, 255, 512, 1023, 1085, 1295, 1505, 1854, 1925, 2048, 2744, 3248, 3303, 3752, 4025, 4095, 4760, 4815, 4865, 5004, 5319, 5768, 6327, 6776, 7104, 7784, 7944, 8154, 8192, 8574, 8792, 8855, 9800, 10254, 10808, 11312, 11816, 11871
OFFSET
1,1
COMMENTS
Positive numbers k such that both k and k + 1 are in A331827.
Numbers of the form 2^(2*k+1) and 2^(2*k) - 1 are terms.
LINKS
MATHEMATICA
negaBinWt[n_] := negaBinWt[n] = If[n==0, 0, negaBinWt[Quotient[n-1, -2]] + Mod[n, 2]]; negBinQ[n_] := And @@ (Divisible[n, negaBinWt[#]] & /@ {-n, n}); nConsec = 2; neg = negBinQ /@ Range[nConsec]; seq = {}; c = 0; k = nConsec + 1; While[c < 45, If[And @@ neg, c++; AppendTo[seq, k - nConsec]]; neg = Join[Rest[neg], {negBinQ[k]}]; k++]; seq
CROSSREFS
Intersection of A331820 and A331821.
Sequence in context: A128022 A011946 A195095 * A166920 A242510 A080206
KEYWORD
nonn,base
AUTHOR
Amiram Eldar, Jan 28 2020
STATUS
approved