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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 for February 24

A109671:
a (1) = 1
; thereafter, for
k ≥ 1
,
a (2 k) = a (k)
, and
a (2 k + 1)
is the smallest positive number such that
| a (2 k  +  1)  −  a (2 k  −  1) |
= a (k)
.
{ 1, 1, 2, 1, 1, 2, 3, 1, 2, 1, 1, 2, 3, 3, 6, 1, 5, ... }
This is a variant of the semi-Fibonacci numbers (A030067). The sequence is self-describing: the sequence of the absolute differences between odd-indexed terms is the sequence itself. It appears that the record values form sequence A038754 and occur at indices of the form
2k  −  1
. It remains an open question whether or not the sequence contains every positive integer (see A169741).