Here is an example of what to buy: Part # RN55D3010F - 301 ohm resistor .30 ea Part # RN55D2210F - 221 ohm resistor .30 ea That gets you to 522 ohms, 1% tolerance. These are in stock.
I really doubt that they would have exactly a523 but you could put a 500 and a 20and a3 in series to make up the difference
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