A245401 Number of nonnegative integers with property that their base 8/7 expansion (see A024649) has n digits.

8, 8, 8, 8, 8, 8, 8, 8, 16, 16, 16, 16, 24, 24, 32, 32, 40, 40, 48, 56, 64, 72, 80, 96, 112, 128, 144, 160, 184, 216, 240, 280, 320, 360, 416, 472, 544, 616, 704, 808, 920, 1056, 1208, 1376, 1576, 1800, 2056, 2352, 2688, 3072, 3512, 4008, 4584

Offset: 1

Author

James Van Alstine, Jul 21 2014

Keywords

• nonn
• base

Comments

The numbers 8-15 are represented by 70, 71, 72, 73, 74, 75, 76, 77 respectively in base 8/7. These are the only integers with two digits, and so a(2)=8.

Crossrefs

Cf. A081848, A024649, A120186.

Programs

Sage

A=[1]
for i in [1..60]:
    A.append(ceil((8-7)/7*sum(A)))
[8*x for x in A]

Formula

a(n) = 8*A120186(n).