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A043452

Numbers having four 7's in base 8.

4095, 8191, 12287, 16383, 20479, 24575, 28671, 29183, 29695, 30207, 30719, 31231, 31743, 32255, 32319, 32383, 32447, 32511, 32575, 32639, 32703, 32711, 32719, 32727, 32735, 32743, 32751, 32759, 32760, 32761, 32762, 32763, 32764, 32765, 32766, 36863, 40959, 45055

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OFFSET

1,1

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

MAPLE

G:= proc(x, c, d) local L, m1, m2;

L:= convert(x, base, 7);

m2:= nops(c);

m1:= min(nops(L), m2);

8^d-1 + add((L[i]-7)*8^(c[i]-1), i=1..m1) - 7*add(8^(c[i]-1), i = m1+1..m2)

end proc: