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Number of i such that |d(i) - d(i-1)| = 1, where Sum_{i=0..m} d(i)*7^i is the base-7 representation of n.
8

%I #11 Oct 28 2018 04:36:06

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

%T 0,0,0,0,1,0,1,0,0,0,0,0,1,0,1,2,1,1,1,1,1,1,0,1,0,0,0,0,1,2,1,2,1,1,

%U 1,0,0,1,0,1,0,0,0,0,0,1,0,1,0,0,0,0,0,1,0,1

%N Number of i such that |d(i) - d(i-1)| = 1, where Sum_{i=0..m} d(i)*7^i is the base-7 representation of n.

%H Iain Fox, <a href="/A037910/b037910.txt">Table of n, a(n) for n = 1..10000</a>

%o (PARI) a(n) = my(c); for(i=2, #n=digits(n, 7), if(abs(n[i]-n[i-1])==1, c++)); c \\ _Iain Fox_, Oct 27 2018

%Y In base b: A037906 (b=3), A037907 (b=4), A037908 (b=5), A037909 (b=6), A037911 (b=8), A037912 (b=9), A037913 (b=10).

%K nonn,base

%O 1,50

%A _Clark Kimberling_