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# User:Charles R Greathouse IV

Vice President of the OEIS and Editor-in-Chief, interested primarily in computational number theory and allied fields.

I can be contacted via my Talk page here, or by email: my first name (charles) at my initials (crg4) dot com. Other email addresses may work as well.

 User:Charles R Greathouse IV/Averages Early draft of an article. User:Charles R Greathouse IV/Chase sequences 'Chase sequences': Axxxxxx refers to Ayyyyyy, which refers to Azzzzzz... User:Charles R Greathouse IV/Favorites Some of my favorite sequences. User:Charles R Greathouse IV/Format Discusses the correct format of b-files and how to repair ill-formatted b-files. User:Charles R Greathouse IV/Junk Disreputable publishers, journals, etc. User:Charles R Greathouse IV/Keywords Information on keywords: when to use them, new ones to add, etc. User:Charles R Greathouse IV/Metadata Plans for OEIS metadata: keywords, categories, the index, etc. User:Charles R Greathouse IV/Pari Some PARI/GP tools. User:Charles R Greathouse IV/Programs Programs in the OEIS: types, format, etc. User:Charles R Greathouse IV/Projects Other mathematical databases, fingerprint databases, and similar projects User:Charles R Greathouse IV/Properties Sequence properties and classes User:Charles R Greathouse IV/Rule of thumb Sequences should take 1 hour to prepare for submission. User:Charles R Greathouse IV/Tables of special primes Types of primes and their densities User:Charles R Greathouse IV/To do Sequences to work on and b-files to fix. User:Charles R Greathouse IV/Vanity Sequences named after their discoverer. User:Charles R Greathouse IV/Wiki Tools for the OEIS wiki.

Projects:

[talk]

## Sequence of the Day for September 21

A115020: Count backwards from 100 in steps of 7.

 { 100, 93, 86, 79, 72, 65, 58, 51, 44, 37, 30, 23, 16, 9, 2 }

This sequence is sometimes used to gauge the concentration ability of a patient with Alzheimer's disease. The arithmetic is simple, but if short-term memory and concentration are compromised, a mistake is likely to occur at some point. Other decrements can be used for this purpose, with the alternative step preferably having no factor in common with 100.

Today is Alzheimer's Awareness Day.

## 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.

## Complaints

I strive to live up to the highest ethical standards. If you feel that I have wrongly rejected one of your sequences (or otherwise failed to meet the expected standards), please leave a note at Complaints About Editing where it will be reviewed. I hope that in all cases you will first contact me (through the pink comment boxes, on my user page, or by email).