A060125 Self-inverse infinite permutation which shows the position of the inverse of each finite permutation in A060117 (or A060118) in the same sequence; or equally, the cross-indexing between A060117 and A060118.

0, 1, 2, 5, 4, 3, 6, 7, 14, 23, 22, 15, 12, 19, 8, 11, 16, 21, 18, 13, 20, 17, 10, 9, 24, 25, 26, 29, 28, 27, 54, 55, 86, 119, 118, 87, 84, 115, 56, 59, 88, 117, 114, 85, 116, 89, 58, 57, 48, 49, 74, 101, 100, 75, 30, 31, 38, 47, 46, 39, 60, 67, 80, 107, 112, 93, 66, 61, 92

Offset: 0

Author

Antti Karttunen, Mar 02 2001

Keywords

• nonn
• base
• look

Comments

PermRank3Aux is a slight modification of rank2 algorithm presented in Myrvold-Ruskey article.

Links

• Antti Karttunen, Table of n, a(n) for n = 0..5040
• W. Myrvold and F. Ruskey, Ranking and Unranking Permutations in Linear Time, Inform. Process. Lett. 79 (2001), no. 6, 281-284.
• Index entries for sequences related to factorial base representation
• Index entries for sequences that are permutations of the natural numbers

Crossrefs

Cf. A060117, A060118, A060126, A060127, A275957, A275958.

Cf. A261220 (fixed points).

Cf. A056019 (compare the scatter plots).

Programs

Maple

with(group); permul := (a,b) -> mulperms(b,a); swap := (p,i,j) -> convert(permul(convert(p,'disjcyc'),[[i,j]]),'permlist',nops(p));
PermRank3Aux := proc(n, p, q) if(1 = n) then RETURN(0); else RETURN((n-p[n])*((n-1)!) + PermRank3Aux(n-1,swap(p,n,q[n]),swap(q,n,p[n]))); fi; end;
PermRank3R := p -> PermRank3Aux(nops(p),p,convert(invperm(convert(p,'disjcyc')),'permlist',nops(p)));
PermRank3L := p -> PermRank3Aux(nops(p),convert(invperm(convert(p,'disjcyc')),'permlist',nops(p)),p);
# a(n) = PermRank3L(PermUnrank3R(n)) or PermRank3R(PermUnrank3L(n)) or PermRank3L(convert(invperm(convert(PermUnrank3L(j), 'disjcyc')), 'permlist', nops(PermUnrank3L(j))))