%I
%S 1,2,3,4,5,6,8,16,24,32,40,48,50,57,64,71,78,85,92,100,107,114,121,
%T 128,135,142,150,157,164,171,178,185,192,200,207,214,221,228,235,242,
%U 250,257,264,271,278,285,292,300,307,314,321,328,335,342,344,351,358
%N Numbers whose base7 digits have equal upvariation and downvariation; see Comments.
%C Suppose that n has baseb digits b(m), b(m1), ..., b(0). The baseb downvariation of n is the sum DV(n,b) of all d(i)d(i1) for which d(i) > d(i1); the baseb upvariation of n is the sum UV(n,b) of all d(k1)d(k) for which d(k) < d(k1). The total baseb variation of n is the sum TV(n,b) = DV(n,b) + UV(n,b). See the guide at A297330.
%H Clark Kimberling, <a href="/A297262/b297262.txt">Table of n, a(n) for n = 1..10000</a>
%e 358 in base7: 1,0,2,1, having DV = 2, UV = 2, so that 358 is in the sequence.
%t g[n_, b_] := Map[Total, GatherBy[Differences[IntegerDigits[n, b]], Sign]];
%t x[n_, b_] := Select[g[n, b], # < 0 &]; y[n_, b_] := Select[g[n, b], # > 0 &];
%t b = 7; z = 2000; p = Table[x[n, b], {n, 1, z}]; q = Table[y[n, b], {n, 1, z}];
%t w = Sign[Flatten[p /. {} > {0}] + Flatten[q /. {} > {0}]];
%t Take[Flatten[Position[w, 1]], 120] (* A297261 *)
%t Take[Flatten[Position[w, 0]], 120] (* A297262 *)
%t Take[Flatten[Position[w, 1]], 120] (* A297263 *)
%Y Cf. A297330, A297261, A297263.
%K nonn,base,easy
%O 1,2
%A _Clark Kimberling_, Jan 15 2018
