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User:Jean-Bernard François

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$whoami?

I'm Jean-Bernard François (aka infofiltrage) born in France the 03/05/69 & DP Engineer (Engineering Graphics Software).

My current blog is Bondissant (almost art from geometry).

I love number theory, mathematics, and of course OEIS.

I only worked under Debian Linux System with LibreOffice, Inkscape and a LiberKey.

Contributions

A099730 | A000302

Useful Links

Others

Collatz | Diophantine | Primes | Number Theory


Sequence of the Day

Sequence of the Day for October 23

A105027 Write numbers in binary under each other; to get the next block of
2k, k   ≥   0,
terms of the sequence, start at
2k
, read diagonals in upward direction and convert to decimal.
{ 0, 1, 3, 2, 6, 5, 4, 7, ... }
This is a permutation of the nonnegative integers (and for
n > 0
, a permutation of the positive integers). Furthermore, for each block of numbers with
k
binary digits, we have a permutation of this block.
........0
........1
......1 0    <- Starting here, the upward diagonals
......1 1    read 11, 10 giving the block 3, 2. 
....1 0 0    <- Starting here, the upward diagonals
....1 0 1    read 110, 101, 100, 111, 
....1 1 0    giving the block 6, 5, 4, 7.
....1 1 1
..1 0 0 0    
..1 0 0 1    
..1 0 1 0
..1 0 1 1
..1 1 0 0
..1 1 0 1
..1 1 1 0
..1 1 1 1