# [seqfan] A001045 General form: k=2^n-k

Sat Dec 5 04:05:23 CET 2009

```*Message: 7
Date: Sat, 05 Dec 2009 01:14:21 +0100
From: Klaus Brockhaus
<**klaus-brockhaus at t-online.de*<klaus-brockhaus at t-online.de>
*>
Subject: [seqfan]  A comment in A001045*
*%C A001045 General form: k=2^n-k.*
*Can someone (the author?) please explain what this means?
*
*
*
1. as you can see : *k=2^n-k *is the same for many seqs.

k=-2;lst={k};Do[k=2^n-k;AppendTo[lst,k],{n,0,4!}];lst(*A083594.*)
k=-1;lst={k};Do[k=2^n-k;AppendTo[lst,k],{n,0,4!}];lst(*A084247, A097073.*)
k=0;lst={k};Do[k=2^n-k;AppendTo[lst,k],{n,0,4!}];lst(*A001045 Jacobsthal
sequence.*)
k=1;lst={k};Do[k=2^n-k;AppendTo[lst,k],{n,0,4!}];lst(*A014113, A078008.*)
k=2;lst={k};Do[k=2^n-k;AppendTo[lst,k],{n,0,4!}];lst(*A140966.*)
k=3;lst={k};Do[k=2^n-k;AppendTo[lst,k],{n,0,4!}];lst(*A154879.*)
k=4;lst={k};Do[k=2^n-k;AppendTo[lst,k],{n,0,4!}];lst(*A115335.*)

2. if frase `*General form*` is Not appropriate for this explanation..
I do Not hold on this.
This is merely a sample/example/observation...
I'm Not insists on name/frase/form ...etc.

p.s.
we have many seqs, wich can be written by one `general` formula(s),
maybe we need some kind of classification, as / or similar as in Biology?
then one derivatives from other...
some kind of order and sence,
and Not ... ten thousands of segs, but Not related to each other...
millions-green-man-born-independently-in-the-different-galaxies-and-have-absolutly-nothing-to-say-to-each-other.
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