A328687 a(n) is the number of decimals in sqrt(n) needed for all digits 0-9 to occur or -1 if n is a perfect square.

-1, 18, 27, -1, 36, 38, 44, 35, -1, 26, 16, 24, 14, 35, 18, -1, 19, 35, 24, 36, 27, 12, 26, 51, -1, 39, 16, 37, 26, 25, 16, 22, 23, 36, 19, -1, 25, 25, 25, 40, 57, 56, 24, 11, 24, 21, 23, 26, -1, 33, 47, 22, 40, 48, 22, 31, 31, 22, 29, 18, 16, 30, 26, -1, 24

Offset

1,2

Comments

All positive terms are >= 10.

Links

Table of n, a(n) for n=1..65.

Example

The decimals for sqrt(2) are .414213562373095048|801688724... and 18 decimals are needed for all digits to occur so a(2) = 18.
The decimals for sqrt(143) are .9582607431|01398021... so a(143) = 10.
The largest term when n < 10^9 is a(232863046) = 229.

Crossrefs

Sequence in context: A284493 A337523 A167336 * A003634 A338383 A338385

Adjacent sequences: A328684 A328685 A328686 * A328688 A328689 A328690

Keyword

sign,base

Author

Lars Blomberg, Oct 25 2019

Status

approved