A329492 a(n) = smallest d such that the sum of digits of 2^d - n is equal to d, or -1 if no such d exists.

0, 2, 4, 6, 3, 10, 103, 9, 5, 18

Offset: 1

Author

N. J. A. Sloane, Nov 16 2019

Keywords

• nonn
• base
• more

Comments

The first open case is 11. Is a(11) = -1? See A329493.

If a(i) = m > 0 then A328882 takes the value -i for the first time at term 2^m-i. For example, the first appearance of -7 in A328882 is at term 2^103 - 7.

Crossrefs

Cf. A328882, A329002, A329493.