Search: id:A129751 Results 1-1 of 1 results found. %I A129751 %S A129751 0,102,101022,101021010222,101021010221010210102222, %T A129751 101021010221010210102221010210102210102101022222, %U A129751 101021010221010210102221010210102210102101022221010210102210102101022210102101022101021010222222 %N 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. %C A129751 Other sequences may be obtained by using different substitutions for '0', '{' and '}'. %D A129751 http://planetmath.org/encyclopedia/VonNeumannInteger.html %H A129751 I.N. Galidakis, Home Page %F A129751 S(n)=n union {n} %e A129751 a(0)=0, a(1)={0}=102, a(2)={0,{0}}=101022, etc. %p A129751 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: %Y A129751 Cf. A129754. %Y A129751 Sequence in context: A163435 A030512 A097725 this_sequence A094095 A074675 A161402 %Y A129751 Adjacent sequences: A129748 A129749 A129750 this_sequence A129752 A129753 A129754 %K A129751 easy,nonn %O A129751 0,2 %A A129751 I.N. Galidakis (jgal(AT)ath.forthnet.gr), May 14 2007 Search completed in 0.001 seconds