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On early microcomputers it was common to have 40 columns of text with the alternative usually being 32 or 64 for technical reasons as well as ambitious 80 column models that became more common as technology improved and prices for memory and dedicated monitors came down.
But the VIC-20 had a rather small 22 column display which makes it very cramped. Did any other microcomputers settle for a simiarly diminutive text mode as the standard for programming in? The only one I can think of is the Bally Astrocade, assuming that we treat the included BASIC cartridge (which displays a 26x11 text mode) as enough to call it a microcomputer and not just a dedicated video game console.
TI-99/4A had 24 lines of 32 columns but only 28 of them were used by the BASIC. So effectively it had 24x28. Its graphic chip was capable of 24x40 text mode but this was not accessible from Basic and required at least a memory extension (base model had only 256 bytes of memory and the 16 KiB of video memory was used for everything).
Looking through the microcomputers of the 70s and 80s, I find a few which supported low enough resolutions that they could fit only 20 characters across on the screen... but other than the Vic-20, no sign of one that displayed less than 32 characters by default. Here's a list of the ones I've checked. Where there wasn't a text mode listed, just a bitmap output, I've mentioned that and assumed 8x8 character sprites:
Less than 32 columns:
(year) cols Machine: text modes
(1974) n/a Altair 8800: No video
(1980) 8 Acorn Atom: Bitmap 64x64 to 256x192 so 8x8 to 32x24
(1983) 16 Sanyo PHC-25: 16x16, 32x16
(1978) 20 Atari 2600: Bitmap 160x192 so 20x24
(1981) 20 BBC Micro: 20x32, 40x25, 40x32, 80x25, 80x32
Would the Wang 720 "programmable calculator" count? It had a cassette tape for storage, and a typeball hooked up to a plotter mechanism. I recall writing a loader that allowed several programs to be written to tape, where the loader allowed a number to be input to select which program to load.