...Seaman

IRAF Group, National Optical Astronomy Observatories, seaman@noao.edu

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...Pence

HEASARC, NASA Goddard Space Flight Center, pence@tetra.gsfc.nasa.gov

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...group

Making allowance for the dual zeroes, 1's complement addition and multiplication also form an integral domain over the N-bit unsigned integers, see ref. 21, for example.

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...permitted.

The encoding algorithm described in §3.4 and §3.5 only uses the characters, 0-9, A-Z and a-r, as expressed in Figure 1.

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...checksum.

This estimate may not be exactly right due to binary and higher order interactions between the characters from excluding the intervening punctuation characters from the strict alpha-numeric encoding.

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...NOAO

The National Optical Astronomy Observatories are operated by the Association of Universities for Research in Astronomy, Inc. under cooperative agreement with the National Science Foundation.

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