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Certainly a common chip in older computers. The only HP machine that I can instantly think of that uses it is the 2100A minicomputer, but there may be others. I don't think any desktop calculators used it. But I was just thinking of all the machine I have here that are stuffed with them -- PDP11/45 (and in the floating point procrssor), other PDP11s. PERQs, Philips P850, etc.
The logic (gates, not individual transistors) diagram for the 74181 (and for that matter the 74182 look-ahead carry chip) are in the Texas Instruments TTL databook.