login
Inverse permutation to A129674.
4

%I #15 Mar 18 2022 21:51:57

%S 3,2,1,5,7,4,6,9,15,8,11,10,12,14,13,17,21,16,19,18,20,23,27,22,24,26,

%T 25,29,31,28,30,33,37,32,35,34,36,39,43,38,40,42,41,45,51,44,47,46,48,

%U 50,49,53,55,52,54,57,63,56,59,58,60,62,61,65,69,64,67,66,68,71,75,70

%N Inverse permutation to A129674.

%C The inversion maintains the cyclic characteristics as described in A129674.

%H Ferenc Adorjan, <a href="/A129675/b129675.txt">Table of n, a(n) for n = 1..10000</a>

%H <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a>

%o (PARI) {pinverse(v)= /* Permutation inverse of a positive sequence */

%o local(n,m,x);n=matsize(v)[2]; x=vector(n);

%o for(i=1,n,if(v[i]<=n,x[v[i]]=i)); return(x)}

%o a=pinverse(A129674)

%Y Inverse of A129674, Cf. A128754, A128755, A129679 and A001969.

%K nonn,base

%O 1,1

%A Ferenc Adorjan (fadorjan(AT)freemail.hu or ferencadorjan(AT)gmail.com), May 01 2007