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%I #11 Aug 08 2015 21:22:44
%S 1,2,4,3,6,8,10,5,7,12,14,16,18,11,20,9,22,24,15,26,13,28,30,19,32,34,
%T 36,38,40,23,42,17,44,21,46,27,48,50,52,31,54,56,58,35,25,60,29,62,64,
%U 66,39,68,70,72,74,43,76,78,37,80,47,82,84,33,86,88,51,90,92,94,96,55
%N Inverse permutation to A101905.
%p A101261 := proc(nmax) local a,n,anex ; a := [1,2] ; while nops(a) < nmax do if nops(a) mod 2 = 0 then a := [op(a),1] ; else n := (nops(a)+1)/2 ; n := op(n,a) ; anex := 2 ; while anex in a or n > 1 do if not anex in a then n := n-1 ; fi ; anex := anex+1 ; od ; a := [op(a),anex] ; fi ; od ; RETURN(a) ; end: A101905 := proc(nmax) local a,n,anex ; a := A101261(2*nmax) ; for n from 2*nmax-1 to 3 by -2 do a := subsop(n=NULL,a) ; od ; RETURN(a) ; end: a := A101905(80) ; n:= 1: while member(n,a,'ninv') do printf("%d, ",ninv) ; n := n+1 : od : # _R. J. Mathar_, May 02 2007
%Y Cf. A101261, A101905.
%K easy,less,nonn
%O 1,2
%A _Leroy Quet_, Dec 20 2004
%E More terms from _R. J. Mathar_, May 02 2007
%E More terms from _David Wasserman_, Mar 31 2008
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