26 Nov
2017
26 Nov
'17
1:40 p.m.
Perhaps it was 2^18-1 ? 2^18+1 ?
No. It was indeed finding "the highest proper divisor" of 2^18 (i.e. 131072). The only arithmetic operations implemented in hardware were subtraction and negation. Divisions had to be implemented by repeated subtractions of the divisor. "The machine was not intended to be a practical computer but was instead designed as a testbed for the Williams tube, an early form of computer memory." http://www.historyofinformation.com/expanded.php?id=858 Alas, 2^18 is written there as 218.