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Number of nonnegative integers with property that their base 7/6 expansion (see A024643) has n digits.
0

%I #12 Jul 22 2014 12:35:04

%S 7,7,7,7,7,7,7,14,14,14,21,21,28,28,35,42,49,56,63,77,91,105,119,140,

%T 161,189,224,259,301,350,413,483,560,651,763,889,1036,1211,1414,1645,

%U 1925,2240,2618,3052,3563,4158,4851,5656,6601,7700,8981,10479,12229,14266

%N Number of nonnegative integers with property that their base 7/6 expansion (see A024643) has n digits.

%F a(n) = 7*A120178(n).

%e a(3) = 7 because 650, 651, 652, 653, 654, 655 and 656 are the base 7/6 expansions for the integers 14, 15, 16, 17, 18, 19 and 20 respectively and these are the only integers with 3 digits.

%o (Sage)

%o A=[1]

%o for i in [1..60]:

%o A.append(ceil(((7-6)/6)*sum(A)))

%o [7*x for x in A]

%Y Cf. A024643, A120178, A072493, A245356.

%K nonn,base

%O 1,1

%A _Hailey R. Olafson_, Jul 21 2014