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.

A057542 Maximum cycle length in each permutation between A038776(1) and A038776(A000108(n)).

Original entry on oeis.org

1, 1, 1, 3, 4, 16, 87, 202, 607, 1441, 4708, 41888, 44741, 339108, 1617551
Offset: 0

Views

Author

Antti Karttunen, Sep 07 2000

Keywords

Crossrefs

Cycle lengths of permutation A038776 given in A038774.
LCM's of all cycles: A060113.

Programs

  • Maple
    map(lmax,Bf2DfBinTreePermutationCycleLengths(some_value)); (e.g. 10)
    bf2df := s -> (btbf2df(binrev(s),0,1)/2); # btbf2df and binrev given in A038776
    Bf2DfBinTreePermutationCycleLengths := proc(upto_n) local u,n,a,r,b; a := []; for n from 0 to upto_n do b := []; u := (binomial(2*n,n)/(n+1)); for r from 0 to u-1 do b := [op(b),1+CatalanRank(n,bf2df(CatalanUnrank(n,r)))]; od; a := [op(a),CycleLengths1(b)]; od; RETURN(a); end;
    CycleLengths1 := b -> [[(nops(b)-convert(map(nops,convert(b,'disjcyc')),`+`)),`*`,1],op(map(nops,convert(b,'disjcyc')))];
    last_term := proc(l) local n: n := nops(l); if(0 = n) then ([]) else (op(n,l)): fi: end:
    lmax := proc(a) local e,z; z := 0; for e in a do if whattype(e) = list then e := last_term(e); fi; if e > z then z := e; fi; od; RETURN(z); end;

Extensions

a(11)-a(14) from Sean A. Irvine, Jun 13 2022