cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A057113 Positions of permutations produced by the transposition sequence A057112 in A055089.

Original entry on oeis.org

0, 1, 4, 5, 3, 2, 12, 13, 16, 22, 19, 18, 20, 10, 7, 6, 8, 14, 15, 9, 11, 21, 23, 17, 77, 76, 73, 72, 74, 75, 85, 84, 86, 80, 78, 79, 82, 92, 90, 91, 94, 88, 89, 95, 93, 83, 81, 87, 63, 62, 60, 61, 64, 65, 71, 70, 67, 53, 51, 50, 48, 54, 56, 57, 59, 69, 68, 58, 55, 49, 52, 66, 108, 109, 112, 113, 111, 110, 104, 105, 107, 117, 119, 118, 115, 101, 99, 98, 96, 102
Offset: 0

Views

Author

Antti Karttunen, Aug 09 2000

Keywords

Crossrefs

PermRevLexRank given in A056019.

Programs

  • Maple
    atp_perm_ranks := proc(upto_n) local t,a,p,i,k; p := convert([1],'disjcyc'); k := nops(factorial_base(upto_n))+1; a := []; for i from 1 to upto_n do a := [op(a),PermRevLexRank(convert(p,'permlist',k))]; t := adj_tp_seq(i); p := mulperms([[t,t+1]],p); od; RETURN(a); end;

Formula

perm_ranks_seq := atp_perm_ranks(120);

A065182 Permutation of nonnegative integers produced when the finite permutations listed by A055089 are subjected to Foata transform. Inverse of A065181.

Original entry on oeis.org

0, 1, 2, 4, 5, 3, 6, 7, 12, 18, 19, 13, 14, 16, 8, 22, 20, 10, 21, 23, 11, 17, 15, 9, 24, 25, 26, 28, 29, 27, 48, 49, 72, 96, 97, 73, 74, 76, 50, 100, 98, 52, 99, 101, 53, 77, 75, 51, 54, 55, 60, 66, 67, 61, 30, 31, 84, 108, 109, 85, 78, 91, 36, 115, 102, 42, 103, 114, 43
Offset: 0

Views

Author

Antti Karttunen, Oct 19 2001

Keywords

Comments

Here we use a variant of Foata's transformation, which forms a new permutation by "inserting parentheses" at each left-right maxima, to delimit cycles.

References

  • I. M. Gessel and R. P. Stanley, Algebraic Enumeration, chapter 21 in Handbook of Combinatorics, Vol. 2, edited by R.L.Graham et al., The MIT Press, Mass, 1995, page 1045.

Crossrefs

A065161-A065163 give cycle counts and max lengths. Cf. also A065183, A065184 and A055089 and A056019 for the requisite Maple procedures.

Programs

  • Maple
    [seq(PermRevLexRank(Foata(PermRevLexUnrank(j))),j=0..119)];
    with(group); Foata := proc(p) local c,c1,i,m; c := []; c1 := []; m := 0; for i from 1 to nops(p) do if(p[i] > m) then if(nops(c1) > 1) then c := [op(c),c1]; fi; m := p[i]; c1 := []; fi; c1 := [op(c1),p[i]]; od; if(nops(c1) > 1) then c := [op(c),c1]; fi; RETURN(convert(c,'permlist',nops(p))); end;
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