You're right
I did a search in Element14 and RS and they are not stocked anymore. There are some on eBay but not cheap either...
http://www.ebay.com/itm/CD74HC181E-RCA-IC-24-Pin-DIP-Vintage-RARE-New-74HC181-/330527108246?pt=LH_DefaultDomain_0&hash=item4cf4f36c96
Luckily the chip was in my proteus simulator and it can still be simulated (74LS181 and 74HC181).
Allen
I did a search in Element14 and RS and they are not stocked anymore. There are some on eBay but not cheap either...
http://www.ebay.com/itm/CD74HC181E-RCA-IC-24-Pin-DIP-Vintage-RARE-New-74HC181-/330527108246?pt=LH_DefaultDomain_0&hash=item4cf4f36c96
Luckily the chip was in my proteus simulator and it can still be simulated (74LS181 and 74HC181).
Allen