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.

Showing 1-7 of 7 results.

A060112 Sums of nonconsecutive factorial numbers.

Original entry on oeis.org

0, 1, 2, 6, 7, 24, 25, 26, 120, 121, 122, 126, 127, 720, 721, 722, 726, 727, 744, 745, 746, 5040, 5041, 5042, 5046, 5047, 5064, 5065, 5066, 5160, 5161, 5162, 5166, 5167, 40320, 40321, 40322, 40326, 40327, 40344, 40345, 40346, 40440, 40441, 40442
Offset: 1

Views

Author

Antti Karttunen, Mar 01 2001

Keywords

Comments

Zeckendorf (Fibonacci) expansion of n (A003714) reinterpreted as a factorial expansion.
Also positions in A055089, A060117 and A060118 of the permutations that are composed of disjoint adjacent transpositions only. (That these positions are same can be seen by comparing algorithms PermRevLexUnrankAMSD, PermUnrank3R, PermUnrank3L in the respective sequences). Thus also positions of the fixed terms in A065181-A065184. See comment at A065163.
Written as disjoint cycles the permutations are: (), (1 2), (2 3), (3 4), (1 2)(3 4), (4 5), (1 2)(4 5), (2 3)(4 5), etc. Apart from the first one (the identity), these are the only kind of permutations used in campanology when moving from one "change" to next.

Examples

			Zeckendorf Expansions of first few natural numbers and the corresponding values when interpreted as factorial expansions: 0 = 0 = 0, 1 = 1 = 1, 2 = 10 = 2, 3 = 100 = 6, 4 = 101 = 7, 5 = 1000 = 24, 6 = 1001 = 25, 7 = 1010 = 26, 8 = 10000 = 120, etc.,
		

Crossrefs

Subset of A059590. Cf. also A001611, A064640.
For PermRevLexRank, see A056019, for fibbinary see A048679 and A003714.

Programs

  • Maple
    CampanoPerm := proc(n) local z,p,i; p := []; z := fibbinary(n); i := 1; while(z > 0) do if(1 = (z mod 2)) then p := permul(p,[[i,i+1]]); fi; i := i+1; z := floor(z/2); od; RETURN(convert(p,'permlist',i)); end;
  • Mathematica
    With[{b = MixedRadix[Range[12, 2, -1]]}, FromDigits[#, b] & /@ Select[Tuples[{0, 1}, 8], SequenceCount[#, {1, 1}] == 0 &]] (* Michael De Vlieger, Jun 26 2017 *)
  • PARI
    fill(lim,k,val)=if(k>#f, return); my(t=val+f[k]); if(t<=lim, listput(v,t); fill(lim,k+2,t)); fill(lim,k+1,val)
    list(lim)=my(k,t=1); local(f=List(),v=List([0])); while((t*=k++)<=lim, listput(f,t)); f=Vecrev(f); fill(lim,1,0); Set(v) \\ Charles R Greathouse IV, Jun 25 2017
    
  • PARI
    first(n) = my(res = [0, 1], k = 1, t = 1, p = 1); while(#res < n, k++; t++; p *= t; res = concat(res, vector(fibonacci(k), i, res[i]+p))); vector(n, i, res[i]) \\ David A. Corneth, Jun 26 2017

Formula

a(n) = PermRevLexRank(CampanoPerm(n))
a(A001611(n)) = (n-1)! for n > 2. - David A. Corneth, Jun 25 2017

A065161 Number of orbits into which the Foata transform partitions the symmetric group Sn, i.e., a(n) is the number of cycles in the permutations A065181 - A065184 found in range [0,n!-1].

Original entry on oeis.org

1, 2, 4, 10, 24, 60, 138, 336, 820, 2114, 5340, 14136
Offset: 1

Views

Author

Antti Karttunen, Oct 19 2001

Keywords

Comments

Counted with the Maple procedure FoataPermutationCycleCounts_Lengths_and_LCM given in A065163.

Crossrefs

Extensions

a(9)-a(12) from Sean A. Irvine, Aug 19 2023

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

Original entry on oeis.org

0, 1, 2, 5, 3, 4, 6, 7, 14, 23, 17, 20, 8, 11, 12, 22, 13, 21, 9, 10, 16, 18, 15, 19, 24, 25, 26, 29, 27, 28, 54, 55, 86, 119, 95, 110, 62, 71, 78, 116, 79, 113, 65, 68, 92, 102, 89, 103, 30, 31, 38, 47, 41, 44, 48, 49, 84, 118, 94, 108, 50, 53, 80, 117, 83, 109, 51, 52
Offset: 0

Views

Author

Antti Karttunen, Oct 19 2001

Keywords

Comments

Here we use the inverse of the left-right maxima variant of Foata's transformation, which works by rotating each cycle largest element first and then sorts the cycles to ascending order, according to that first (and largest) element of each.

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(FoataInv(PermRevLexUnrank(j))),j=0..119)];
    with(group); FoataInv := p -> map(op, sort([op(map(RotCycleLargestFirst,convert(p,`disjcyc`))),op(FixedCycles(p))], sortbyfirst));
    sortbyfirst := (a,b) -> `if`((a[1] < b[1]),true,false);
    FindLargest := proc(a) local i,m; m := 0; for i from 1 to nops(a) do if(0 = m) then m := i; else if(a[i] > a[m]) then m := i; fi; fi; od; RETURN(m); end;
    RotCycleLargestFirst := proc(c) local x; x := FindLargest(c); if(x <= 1) then RETURN(c); else RETURN([op(c[x..nops(c)]),op(c[1..(x-1)])]); fi; end;
    FixedCycles := proc(p) local a,i; a := []; for i from 1 to nops(p) do if(p[i] = i) then a := [op(a),[i]]; fi; od; RETURN(a); end;

A065184 Permutation of nonnegative integers produced when the finite permutations listed by A060117 are subjected to the left-right maxima variant of Foata's transformation. Inverse of A065183.

Original entry on oeis.org

0, 1, 2, 5, 3, 4, 6, 7, 14, 23, 15, 22, 8, 21, 12, 16, 19, 11, 17, 10, 9, 13, 20, 18, 24, 25, 26, 29, 27, 28, 54, 55, 86, 119, 87, 118, 56, 117, 84, 88, 115, 59, 89, 58, 57, 85, 116, 114, 30, 31, 80, 107, 81, 106, 48, 49, 60, 67, 61, 66, 74, 92, 38, 113, 47, 101, 112, 100
Offset: 0

Views

Author

Antti Karttunen, Oct 19 2001

Keywords

Crossrefs

A065161-A065163 give cycle counts and max lengths. Cf. also A065181, A065182 for Maple procedure Foata and A060117 for PermUnrank3R and A060125 for PermRank3R.

Programs

  • Maple
    [seq(PermRank3R(Foata(PermUnrank3R(j))),j=0..119)];

A065183 Permutation of nonnegative integers produced when the finite permutations listed by A060117 are subjected to the inverse of (variant of) Foata's transformation. Inverse of A065184.

Original entry on oeis.org

0, 1, 2, 4, 5, 3, 6, 7, 12, 20, 19, 17, 14, 21, 8, 10, 15, 18, 23, 16, 22, 13, 11, 9, 24, 25, 26, 28, 29, 27, 48, 49, 78, 108, 103, 91, 74, 111, 62, 69, 75, 104, 101, 94, 100, 83, 71, 64, 54, 55, 80, 109, 107, 90, 30, 31, 36, 44, 43, 41, 56, 58, 72, 110, 106, 77, 59, 57, 81
Offset: 0

Views

Author

Antti Karttunen, Oct 19 2001

Keywords

Crossrefs

A065161-A065163 give cycle counts and max lengths. Cf. also A065182, A065181 for Maple procedure FoataInv and A060117 for PermUnrank3R and A060125 for PermRank3R.

Programs

  • Maple
    [seq(PermRank3R(FoataInv(PermUnrank3R(j))),j=0..119)];

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;

A065162 Least common multiple of all orbit sizes (cycle lengths in corresponding permutations A065181-A065184) into which the Foata transform partitions the symmetric group Sn.

Original entry on oeis.org

1, 1, 3, 84, 392700, 134303400, 144049802170012200, 20408430429061596071366416200, 44398211066986010729368646573034503961122478555908400, 265062009098171901647881980851886506540968043007100873153849200
Offset: 1

Views

Author

Antti Karttunen, Oct 19 2001

Keywords

Comments

Counted with the Maple procedure FoataPermutationCycleCounts_Lengths_and_LCM given in A065163.

Crossrefs

Extensions

More terms from Sean A. Irvine, Aug 19 2023
Showing 1-7 of 7 results.