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Down-variation of the base-16 digits of n; see Comments.
4

%I #5 Jan 18 2018 19:35:28

%S 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,1,0,

%T 0,0,0,0,0,0,0,0,0,0,0,0,0,3,2,1,0,0,0,0,0,0,0,0,0,0,0,0,0,4,3,2,1,0,

%U 0,0,0,0,0,0,0,0,0,0,0,5,4,3,2,1,0,0

%N Down-variation of the base-16 digits of n; see Comments.

%C Suppose that a number 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). Every positive integer occurs infinitely many times. See A297330 for a guide to related sequences and partitions of the natural numbers.

%H Clark Kimberling, <a href="/A297246/b297246.txt">Table of n, a(n) for n = 1..10000</a>

%e 32 in base 15: 2,0; here DV = 2, so that a(32) = 2.

%t g[n_, b_] := Differences[IntegerDigits[n, b]];

%t b = 16; z = 120; Table[-Total[Select[g[n, b], # < 0 &]], {n, 1, z}]; (* A297246 *)

%t Table[Total[Select[g[n, b], # > 0 &]], {n, 1, z}]; (* A297247 *)

%Y Cf. A297247, A297248, A297330.

%K nonn,base,easy

%O 1,32

%A _Clark Kimberling_, Jan 18 2018

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Last modified September 22 18:47 EDT 2024. Contains 376138 sequences. (Running on oeis4.)