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 Welcome to the OEIS wiki, the wiki complement to the On-Line Encyclopedia of Integer Sequences. 179,125 articles.

## Editor's Guide

• A239797 Decimal expansion of $\frac{\sqrt{3}}{\sqrt[3]{4}}$.
• A238271 Decimal expansion of $\sum_{n =1}^\infty \frac{\mu(n)}{3^n}$.
• A237042 UPC check digits.
• A236603 Lowest canonical Gray cycles of length 2n.
• A235365 Smallest odd prime factor of 3n + 1.
• A234522 Decimal expansion of $\sqrt[4]{7} - \sqrt[4]{5}$.
• A233748 Number of graphs on n vertices with edges colored with at most four interchangeable colors under the symmetries of the full edge permutation group.
• A232499 Number of unit squares, aligned with a Cartesian grid, completely within the first quadrant of a circle centered at the origin ordered by increasing radius.
• A231963 Concatenate n with its UPC check digit.
• A230624 Numbers n with property that for every base $b \geq 2$, there is a number m such that m + s(m) = n, where s(m) is the sum of digits in the base b expansion of m.

## Sequence of the Day for December 16

A054245: Beethoven's Symphony No. 5 in C minor.

 { 5, 5, 5, 3, 4, 4, 4, 2, 5, 5, 5, 3, 6, 6, 6, 5, 10, 10, 10, 8, 5, 5, 5, ... }

Contrary to popular belief, the first movement of Beethoven's Fifth Symphony has an eight-note motif, not four notes. Here of course we have just the principal melody line, without the bass line and inner voices. Before "polyphonic" ring tones became available, this is how you would hear it as a ring tone.

Compare:

Beethoven - Symphony No. 5 in C Minor (1) (Symphony no. 5 in C minor Op. 67 — 1. Allegro con brio)
http://oeis.org/A054245/listen (Pitch offset of 40 works somewhat better, sort of...)
Today is Beethoven's birthday, by the way.

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## On this day...

• December 16, 1752 Leonhard Euler replies to Christian Goldbach confirming that his conjecture on numbers of the form 2n2 + p holds true up to 1000. (See A042978).
• December 16, 1893 Kurt Heegner is born in Berlin.
• December 16, 1933 Ludwig Schlesinger dies in Giessen.

## Sequences in the News

• November 18, 2016 PrimeGrid proves that 10223 is not a Sierpinski number, since 10223 × 2 31172165 + 1 is prime. So no changes to A076336 for now.
• September 14, 2016 Tom Greer discovers the twin primes 2996863034895 × 2 1290000 ± 1 using PrimeGrid, TwinGen and LLR.
• January 19, 2016 Largest known term of A000043 announced: 274207281, also discovered by Curtis Cooper.
• March 2, 2014 Fredrik Johansson announces a computation of the partition number $\scriptstyle p(10^{20}) \approx 1.8381765\cdot10^{11140086259}$, the largest known term of A000041.
• December 6, 2013 Microsoft launches a challenge to find large non-Mersenne primes, A138837.
• May 13, 2013 H. A. Helfgott submits a proof of the weak Goldbach conjecture, i.e. for odd numbers as sums of three primes: A007963 has no more zeroes.
• January 25, 2013 Curtis Cooper discovers a new member of A000043, 57885161. Its index is not known but is at least 48.
• January 13, 2013 The winners of the contest for new sequences in the OEIS at JMM 2013 were announced: A187824, A187771, and A187761.

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