A032942 - OEIS

%I #14 Feb 12 2021 22:04:33

%S 1,2,3,4,5,6,7,14,21,28,35,42,49,50,51,52,53,54,55,98,99,100,101,102,

%T 103,104,147,148,149,150,151,152,153,196,197,198,199,200,201,202,245,

%U 246,247,248,249,250,251,294,295,296,297,298

%N Numbers whose base-7 representation Sum_{i=0..m} d(i)*7^(m-i) has d(i)=0 for all odd i.

%H Robert Israel, <a href="/A032942/b032942.txt">Table of n, a(n) for n = 1..10000</a>

%p f:= proc(n, j) local L, m;

%p   L:= convert(n, base, 5);

%p   m:= nops(L);

%p   j*add(L[i+1]*7^(2*i), i=0..m-1)

%p end proc: seq(seq(seq(f(n, j), n=7^k..7^(k+1)-1), j=[1, 7]), k=0..2); # _Robert Israel_, Nov 16 2020

%Y Cf. A007093 (numbers in base 7).

%K nonn,base

%O 1,2

%A _Clark Kimberling_

%E Definition corrected by _Robert Israel_, Nov 16 2020