|
| |
|
|
A129751
|
|
The natural numbers represented by their set theoretic Von Neumann construction, where the empty set is replaced by '0', the left set bracket '{' is replaced by 1, the right bracket '}' is replaced by 2 and the set construct contents are ordered by increasing cardinality.
|
|
1
| |
|
|
0, 102, 101022, 101021010222, 101021010221010210102222, 101021010221010210102221010210102210102101022222, 101021010221010210102221010210102210102101022221010210102210102101022210102101022101021010222222
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,2
|
|
|
COMMENTS
| Other sequences may be obtained by using different substitutions for '0', '{' and '}'.
|
|
|
REFERENCES
| http://planetmath.org/encyclopedia/VonNeumannInteger.html
|
|
|
LINKS
| I.N. Galidakis, Home Page
|
|
|
FORMULA
| S(n)=n union {n}
|
|
|
EXAMPLE
| a(0)=0, a(1)={0}=102, a(2)={0,{0}}=101022, etc.
|
|
|
MAPLE
| N:=proc(n) local i, s, l, r, data; s:=`0`; l:=`1`; r:=`2`; #change here for different sequences if n>0 then for i from 1 to n-1 do s:=cat(s, l, s, r); od; s:=cat(l, s, r); fi; data:=sscanf(s, `%d`); RETURN(data[1]); end:
|
|
|
CROSSREFS
| Cf. A129754.
Sequence in context: A203401 A030512 A097725 * A094095 A187882 A074675
Adjacent sequences: A129748 A129749 A129750 * A129752 A129753 A129754
|
|
|
KEYWORD
| easy,nonn
|
|
|
AUTHOR
| I.N. Galidakis (jgal(AT)ath.forthnet.gr), May 14 2007
|
| |
|
|
