A297273 Numbers whose base-11 digits have greater down-variation than up-variation; see Comments.

11, 22, 23, 33, 34, 35, 44, 45, 46, 47, 55, 56, 57, 58, 59, 66, 67, 68, 69, 70, 71, 77, 78, 79, 80, 81, 82, 83, 88, 89, 90, 91, 92, 93, 94, 95, 99, 100, 101, 102, 103, 104, 105, 106, 107, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 121, 132, 143, 154

Offset

1,1

Comments

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.

Links

Clark Kimberling, Table of n, a(n) for n = 1..10000

Example

154 in base-11:  1,3,0, having DV = 3, UV = 2, so that 154 is in the sequence.

Mathematica

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 = 11; 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]   (* A297273 *)
Take[Flatten[Position[w, 0]], 120]    (* A297274 *)
Take[Flatten[Position[w, 1]], 120]    (* A297275 *)

Crossrefs

Cf. A297330, A297274, A297275.

Sequence in context: A048136 A180054 A166713 * A296746 A095779 A062055

Adjacent sequences: A297270 A297271 A297272 * A297274 A297275 A297276

Keyword

nonn,base,easy

Author

Clark Kimberling, Jan 16 2018

Status

approved