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A327478
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Numbers whose average binary index is also a binary index.
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4
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1, 2, 4, 7, 8, 14, 16, 21, 28, 31, 32, 39, 42, 56, 57, 62, 64, 73, 78, 84, 93, 107, 112, 114, 124, 127, 128, 141, 146, 155, 156, 168, 175, 177, 186, 214, 217, 224, 228, 245, 248, 254, 256, 267, 273, 282, 287, 292, 310, 312, 313, 336, 341, 350, 354, 371, 372
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OFFSET
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1,2
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COMMENTS
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A binary index of n is any position of a 1 in its reversed binary expansion. The binary indices of n are row n of A048793.
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LINKS
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EXAMPLE
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The sequence of terms together with their binary indices begins:
1: 1
2: 2
4: 3
7: 1 2 3
8: 4
14: 2 3 4
16: 5
21: 1 3 5
28: 3 4 5
31: 1 2 3 4 5
32: 6
39: 1 2 3 6
42: 2 4 6
56: 4 5 6
57: 1 4 5 6
61: 2 3 4 5 6
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MATHEMATICA
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bpe[n_]:=Join@@Position[Reverse[IntegerDigits[n, 2]], 1];
Select[Range[100], MemberQ[bpe[#], Mean[bpe[#]]]&]
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CROSSREFS
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Numbers whose binary indices have integer mean are A326669.
Cf. A000016, A000120, A029931, A048793, A065795, A070939, A237984, A240850, A327473, A327474, A327481.
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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