Numeric placeholders such as the {LAYER_SEQ} can be formatted by the user.
On the one hand, you can influence the number format with a ":". {LAYER_SEQ:000}, for example, ensures that the sequence number is always output with three digits (leading zeros if necessary).
In addition, you can define an offset with a "#" if you want to influence the start value.
If you want to define both an offset and a format, the offset comes first and then the format. Example: {LAYER_SEQ#1:000} (Layer sequence number with offset 1 and a format of three digits, where leading zeros are output. Sequence number 8 is output as "007" in the example.
Formatting options
Simple formatting rules
Format (formatting chain)  Description  DescriptionExample 
D or d 
Output of the value as an integer, the precision specifies the minimum number of digits required. 
1234 (D) → 1234 1234 (D6) → 001234 
X or x 
Output of the value as a hexadecimal value, the precision indicates the minimum number of digits required. 
255 (X) → FF 255 (x) → ff 255 (x4) → 00ff 
ABC or abc 
Output of the numerical value as letters of the alphabet (where a corresponds to the value 1). 
2 (ABC) → B 2 (abc) → b 26 (ABC) → Z 27 (ABC) → AA 
Custom formatting rule
The custom formatting rules consist of placeholders that can be freely combined to write a corresponding formatting expression.
Platzhalter  Beschreibung  Beispiel 
0

Replaces the digit 0 with a corresponding existing digit if necessary; otherwise the digit 0 is displayed in the result. 
1234 (00000) → 01234 
#

Replaces the # symbol with a corresponding existing digit if necessary; otherwise, no digit is displayed in the result. 
1234 (#####) → 1234 
.

Determines the position of the decimal separator in the result string. 
1234 (####.0) → 1234,0 
,

The character is used both as an identifier for group separators and as an identifier for number scaling. When used as a group separator identifier, a localized separator is inserted between each group. When used as a number scaling identifier, a number is divided by 1000 for each specified character. 
Separator: 1234 (##,#) → 1.234 1234567 (#,#) → 1.234.567
Scaling: 1234 (#,#,) → 1 1234567 (#,#,) → 1.234 
%

Multiplies a number by 100 and inserts a percentage symbol in the result string. 
1 (%) → 100% 
‰

Multiplies a number by 1000 and inserts a per mil symbol in the result string. 
1 (‰) → 1000‰ 
E0 or E+0 or E0 
Format the result with the exponential notation if it is followed by 0 at least once. E can be written in lower case to write the E in the result in lower case. The + sign indicates that the exponent is always preceded by a sign. A  or no sign indicates that only negative exponents get a sign. 
1234 (#0.0e0) → 12,3e2 1234 (0.0E+0) → 1,2E+3 