Nobody Fears Track 13

Hotels skip the thirteenth floor; airlines skip row 13. Do albums skip track 13? The database holds track listings for 2,813,936 studio-album discs, so the superstition is testable. Here is how many albums end at each length:

At first glance the case looks open-and-shut: 336,985 twelve-track albums, then a plunge to 195,378 at thirteen. A 42% cliff! Guilty!

Except look at the other odd numbers. Every odd count sits in a notch between its even neighbors — the whole chart is a sawtooth laid over a slope. Measure each odd number against the geometric mean of its neighbors and track 13's dip (0.84) is *milder* than 11's (0.80) and much milder than 9's (0.75). If albums feared thirteen the way hotels do, 13 would dip more than its odd siblings. It dips less. Verdict: acquitted. Nobody sequencing an album in a studio at 3 a.m. is counting on their fingers for the devil.

What the chart actually reveals is a different superstition, so universal nobody calls it one: evenness. Ten is the modal album — 396,703 discs, the round number the LP era standardized and the CD era never shook — with twelve close behind. Albums end on even numbers for the same reason setlists do and symphonies don't: the format was born from two vinyl sides, and balance got into the culture's fingers. The market's true lucky numbers are 10 and 12; odd counts are what happens when the material wins the argument with the sequence.

(And the left edge of the chart has its own story: 43,188 two-track discs — the singles — and 35,145 with exactly one track, the album-as-single-piece format that everyone from Jethro Tull to sludge metal keeps re-inventing.)

The man who ran toward it

If anyone in recorded music deserves the last word on 13, it's Thelonious Monk — a man whose relationship with numbers, dates, and superstitions ran opposite to everyone else's. At a Prestige session with Sonny Rollins that fell on a Friday the 13th, Monk didn't reschedule; he wrote the date into the music. The composition Friday the 13th now has 56 recordings in the database: a dozen by Monk himself, then Steve Lacy within six years, Milt Jackson, the Monk-alumni band Sphere in 1982 — the year Monk died — and, eventually, Todd Rundgren. Hotels renumber their floors; Monk pressed the number to vinyl and fifty-five more tapes agreed with him. (His birthday, the graph notes, was October 10 — 10/10, a doubled date like the ones clerks invent, except his was real.)

Method: track counts per medium (disc) of primary-type Album, non-compilation release groups, from position data on the recording-release links; multi-disc albums contribute each disc separately; counts capped at 60 tracks for sanity. Odd-number dip = count ÷ geometric mean of the two even neighbors. Computed August 2026 against the 2026-07-25 MusicBrainz build.