vim, $99999 $110000

i$=&ul*&mfd+&ur

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Uses the expression register to insert the expression ul * mfd + ur, using the default values of the respective options:

ul   undolevels    default 1000
mfd  maxfuncdepth  default 100
ur   undoreload    default 10000

vim, $99999 $110000 $120000

i$=&pvh*&ur

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Uses the expression register (note that there is a <C-r> character, which is invisible in most fonts, between the $ and =, for a total of 13 bytes) to insert the value of the 'pvh' option times the value of the 'ur' option.

'previewheight' is the option that controls the height of preview windows, which is 12 by default.

'undoreload' is the maximum number of lines a buffer can have before vim gives up on storing it in memory for undo, and it defaults to 10,000.

vim, $99999

:h*
$yhZZgr$ppppp

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I'm sure I can do better, but it's a start. The current strategy opens the help page for *, the first line of which reads

                            *star* *E348* *E349*

It then grabs the 9 ($yh), closes the help page (ZZ), inserts a dollar sign (gr$) and pastes the 9 five times (ppppp).

vim, $99999 $110000

i$=&ul*&mfd+&ur

Try it online!

Uses the expression register to insert the expression ul * mfd + ur, using the default values of the respective options:

ul   undolevels    default 1000
mfd  maxfuncdepth  default 100
ur   undoreload    default 10000