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A297282
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Numbers whose base-14 digits have greater down-variation than up-variation; see Comments.
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4
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14, 28, 29, 42, 43, 44, 56, 57, 58, 59, 70, 71, 72, 73, 74, 84, 85, 86, 87, 88, 89, 98, 99, 100, 101, 102, 103, 104, 112, 113, 114, 115, 116, 117, 118, 119, 126, 127, 128, 129, 130, 131, 132, 133, 134, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 154
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OFFSET
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1,1
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COMMENTS
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Suppose that n has base-b digits b(m), b(m-1), ..., b(0). The base-b down-variation of n is the sum DV(n,b) of all d(i)-d(i-1) for which d(i) > d(i-1); the base-b up-variation of n is the sum UV(n,b) of all d(k-1)-d(k) for which d(k) < d(k-1). The total base-b variation of n is the sum TV(n,b) = DV(n,b) + UV(n,b). See the guide at A297330.
Differs from A296755 first for 224 = 120_14, which is in this sequence because DV(224,14) = 2 > UV(224,14)=1, but not in A296755 because the number of rises equals the number of falls. - R. J. Mathar, Jan 23 2018
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LINKS
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EXAMPLE
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154 in base-14: 11,0 having DV = 9, UV = 0, so that 154 is in the sequence.
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MATHEMATICA
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g[n_, b_] := Map[Total, GatherBy[Differences[IntegerDigits[n, b]], Sign]];
x[n_, b_] := Select[g[n, b], # < 0 &]; y[n_, b_] := Select[g[n, b], # > 0 &];
b = 14; z = 2000; p = Table[x[n, b], {n, 1, z}]; q = Table[y[n, b], {n, 1, z}];
w = Sign[Flatten[p /. {} -> {0}] + Flatten[q /. {} -> {0}]];
Take[Flatten[Position[w, -1]], 120] (* A297282 *)
Take[Flatten[Position[w, 0]], 120] (* A297283 *)
Take[Flatten[Position[w, 1]], 120] (* A297284 *)
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CROSSREFS
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KEYWORD
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nonn,base,easy
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AUTHOR
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STATUS
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approved
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