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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.
18
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
0,3
COMMENTS
PermRank3Aux is a slight modification of rank2 algorithm presented in Myrvold-Ruskey article.
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))))
CROSSREFS
Cf. A261220 (fixed points).
Cf. A056019 (compare the scatter plots).
Sequence in context: A265362 A264989 A328625 * A265361 A328626 A265357
KEYWORD
nonn,base,look
AUTHOR
Antti Karttunen, Mar 02 2001
STATUS
approved