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User:Charles R Greathouse IV
From OeisWiki
Trustee and Editor-in-Chief, interested primarily in computational number theory.
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/Projects | Other mathematical databases, fingerprint databases, and similar projects |
User:Charles R Greathouse IV/Tables of special primes | Types of primes and their densities |
User:Charles R Greathouse IV/Rule of thumb | Sequences should take 1 hour to prepare for submission. |
User:Charles R Greathouse IV/Chase sequences | 'Chase sequences': Axxxxxx refers to Ayyyyyy, which refers to Azzzzzz... |
User:Charles R Greathouse IV/Programs | Programs in the OEIS: types, format, etc. |
User:Charles R Greathouse IV/Properties | Sequence properties and classes |
User:Charles R Greathouse IV/Metadata | Plans for OEIS metadata: keywords, categories, the index, etc. |
User:Charles R Greathouse IV/Favorites | Some of my favorite sequences. |
User:Charles R Greathouse IV/Keywords | Information on keywords: when to use them, new ones to add, etc. |
User:Charles R Greathouse IV/To do | Sequences to work on and b-files to fix. |
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/Pari | Some Pari tools. |
User:Charles R Greathouse IV/Wiki | Tools for the OEIS wiki. |
Projects:
Useful links:
- Features Wishlist, User:Russ Cox/OEIS Server Features, Suggested Projects
- Deleted sequences
- Suggested pre-submit checklist
- Requested articles
- Editing history: sequence, wiki
- References on proof attempts: P vs. NP, Riemann hypothesis
Sequence of the Day for July 26
A034872: Central column of Lozanić's triangle.
{ 1, 1, 1, 2, 4, 6, 10, 19, 38, 66, 126, 236, 472, 868, ... }
Note that although the values of odd-numbered columns are only listed once, they appear twice in the triangle.
A005418 Row sums
| |||||||||||||||||||||||||||||
| 1 | 1 | |||||||||||||||||||||||||||
1 | 1 | 1 | 2 | ||||||||||||||||||||||||||
2 | 1 | 1 | 1 | 3 | |||||||||||||||||||||||||
3 | 1 | 2 | 2 | 1 | 6 | ||||||||||||||||||||||||
4 | 1 | 2 | 4 | 2 | 1 | 10 | |||||||||||||||||||||||
5 | 1 | 3 | 6 | 6 | 3 | 1 | 20 | ||||||||||||||||||||||
6 | 1 | 3 | 9 | 10 | 9 | 3 | 1 | 36 | |||||||||||||||||||||
7 | 1 | 4 | 12 | 19 | 19 | 12 | 4 | 1 | 72 |
Sequences in the News
- January 19, 2016 Largest known term of A000043 announced: 274207281, also discovered by Curtis Cooper.
- March 2, 2014 Fredrik Johansson announces he's computed p(10^{20}), which he says is approximately 1.8381765 × 10^{ 11140086259}. Once confirmed and verified, it will be 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.
- September 21, 2012 Nick Berry, founder of Data Genetics, finds that the 17th most common 10-digit ATM PIN is 3141592654 (see A011546).
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).