An autogram (Ancient Greek: αὐτός = self, γράμμα = letter) is a sentence that describes itself in the sense of providing an inventory of its own characters.
This sentence employs two a's, two c's, two d's, twenty-eight e's, five f's, three g's, eight h's, eleven i's, three l's, two m's, thirteen n's, nine o's, two p's, five r's, twenty-five s's, twenty-three t's, six v's, ten w's, two x's, five y's, and one z.The first autogram to be published was composed by Sallows in 1982 and appeared in Douglas Hofstadter's "Metamagical Themas" column in Scientific American.
Only the fool would take trouble to verify that his sentence was composed of ten a's, three b's, four c's, four d's, forty-six e's, sixteen f's, four g's, thirteen h's, fifteen i's, two k's, nine l's, four m's, twenty-five n's, twenty-four o's, five p's, sixteen r's, forty-one s's, thirty-seven t's, ten u's, eight v's, eight w's, four x's, eleven y's, twenty-seven commas, twenty-three apostrophes, seven hyphens and, last but not least, a single !The task of producing an autogram is perplexing because the object to be described cannot be known until its description is first complete.
This pangram contains four as, one b, two cs, one d, thirty es, six fs, five gs, seven hs, eleven is, one j, one k, two ls, two ms, eighteen ns, fifteen os, two ps, one q, five rs, twenty-seven ss, eighteen ts, two us, seven vs, eight ws, two xs, three ys, & one z.Sallows wondered if one could produce a pangram that counts its letters as percentages of the whole sentence–a particularly difficult task since such percentages usually won't be exact integers.
Here follows a chain of length 2:[13][14] A special kind of autogram is the 'reflexicon' (short for "reflexive lexicon"), which is a self-descriptive word list that describes its own letter frequencies.
The constraints on reflexicons are much tighter than on autograms because the freedom to choose alternative words such as "contains", "comprises", "employs", and so on, is lost.
Sallows has made an extensive computer search and conjectures that there exist only three pure (i.e., no dummy text) English reflexicons.