What is the smallest uninteresting (natural) number? I’d run across this question before it first appeared in TV program QI.
One approach is to say “all natural numbers are interesting”, so there are no uninteresting numbers. Indeed, the On-Line Encyclopedia of Integer Sequences (OEIS) has sequence number 27, which is the natural numbers. But this approach doesn’t work. The OEIS list of natural numbers stops at number 77, so says in effect that “77 is interesting as the 77th natural number” but “78 is not interesting as the 78th natural number”. For 78 to be interesting it has to be in some other sequence of numbers, and it is, currently in 14418 other sequences.
Another approach is to say, “if a number is the smallest uninteresting number then that in itself makes it interesting”. So if it’s not interesting then it is interesting and vice versa. Again, this approach doesn’t work, because more numbers are added to the collection of interesting numbers all the time.So “the smallest natural number” is only a transitory phenomenon.
Let’s look at the smallest uninteresting number from a historical perspective.
14 is the first uninteresting number, according to Weird Al Yankovic. Other early claims include:
39 is the first uninteresting number, in the 1986 first edition of “The Penguin Dictionary of Curious and Interesting Numbers” by David Wells.
51, in the second edition of the same book.
338, from the webpage http://math.crg4.com/uninteresting.html, 2006 version.
488, ditto 2009 version.
None of the above five numbers are based on the lists in the OEIS. Claims for the first uninteresting number based on non-appearance in the OEIS start with:
8795, by Ingo Althofer in March 2008.
11630, by Nathaniel Johnson in June 2009.
This contribution is recognised by the OEIS itself. 11630 is the fifth number in the sequence a(n) = (n^6 + 2n^5 + 2n^4 + n^3 + 2n)/2. and the comment is “Before this sequence, 11630 was an uninteresting number.
But now 11630 appears in eight sequences in the OEIS, so is not longer interesting because it is uninteresting.
Other numbers that at one time didn’t appear in the OEIS along with 11630 are 12067, 12407, 12887, 13258, 13794, 13882, 13982, 14018, 14163, 14180, 14194. All these are now interesting.
12067 appears ten times. For example it’s interesting because it’s in the list of “Number of irreducible representations of the symmetric group S_n such that their degree is divisible by 3.”
12407, quite widely quoted on as the smallest uninteresting number, was the smallest uninteresting number from November 2009 until at least November 2011, now it appears seven times, for example as the fourth number in the “Numerator of Hermite(n, 19/26).”
13794 appears eight times. It was the smallest uninteresting number from April 2012 until 2 Nov 2012.
14228 appears four times. It was the smallest uninteresting number from 3 Nov 2012 until at least the start of Apr 2015. It’s interesting as a power of 2 with all the digit 0s suppressed.
14972 appears three times. It was the smallest uninteresting number in Nov 2015 but is no longer uninteresting.
So, what is the smallest uninteresting number now?