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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A275834 Positions of even terms in A275832; indices of those permutations in tables A060117 & A060118 where element 1 is in an even cycle.

Original entry on oeis.org

1, 4, 7, 9, 11, 15, 16, 17, 18, 20, 21, 23, 25, 28, 31, 34, 37, 40, 43, 46, 49, 51, 53, 55, 58, 66, 68, 70, 75, 76, 77, 85, 88, 90, 91, 92, 96, 98, 99, 101, 102, 104, 106, 108, 109, 110, 115, 118, 121, 124, 127, 129, 131, 135, 136, 137, 138, 140, 141, 143, 145, 148, 151, 153, 155, 159, 160, 161, 162, 164, 165, 167, 169, 172, 175, 177, 179
Offset: 1

Views

Author

Antti Karttunen, Aug 11 2016

Keywords

Comments

Equally: positions of even terms in A275726.

Crossrefs

Complement: A275833.
A subsequence of A273670 and A275814.

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)];

A275803 a(n) = A051903(A275725(n)); maximal cycle sizes of finite permutations listed in the order A060117 / A060118.

Original entry on oeis.org

1, 2, 2, 3, 2, 3, 2, 2, 3, 4, 3, 4, 2, 3, 3, 4, 2, 4, 2, 3, 2, 4, 3, 4, 2, 2, 2, 3, 2, 3, 3, 3, 4, 5, 4, 5, 3, 4, 4, 5, 3, 5, 3, 4, 3, 5, 4, 5, 2, 2, 3, 4, 3, 4, 3, 3, 4, 5, 4, 5, 2, 3, 4, 5, 3, 5, 2, 3, 3, 5, 4, 5, 2, 3, 3, 4, 2, 4, 2, 3, 4, 5, 3, 5, 3, 4, 4, 5, 3, 5, 2, 4, 3, 5, 3, 5, 2, 3, 2, 4, 3, 4, 2, 3, 3, 5, 4, 5, 2, 4, 3, 5, 3, 5, 3, 4, 3, 5, 4, 5, 2
Offset: 0

Views

Author

Antti Karttunen, Aug 10 2016

Keywords

Examples

			For n=27, which in factorial base (A007623) is "1011" and encodes (in A060118-order) permutation "23154" with one 3-cycle and one 2-cycle, the longest cycle has three elements, thus a(27) = 3.
		

Crossrefs

Cf. A261220 (gives the positions of 1 and 2's).
Differs from A060131 for the first time at n=27, where a(27) = 3, while A060131(27) = 6.

Programs

Formula

a(n) = A051903(A275725(n)).

A275813 Positions of odd terms in A060131; indices of permutations of an odd order in tables A060117 & A060118.

Original entry on oeis.org

0, 3, 5, 8, 10, 13, 14, 19, 22, 30, 33, 35, 36, 39, 41, 42, 45, 47, 50, 52, 54, 57, 59, 63, 65, 69, 71, 73, 74, 81, 83, 84, 87, 89, 93, 95, 97, 100, 105, 107, 111, 113, 114, 117, 119, 144, 147, 149, 152, 154, 157, 158, 163, 166, 168, 171, 173, 176, 178, 181, 182, 187, 190, 192, 195, 197, 200, 202, 205, 206, 211, 214, 216, 219, 221
Offset: 0

Views

Author

Antti Karttunen, Aug 10 2016

Keywords

Comments

Indexing starts with zero, because a(0) = 0 (indicating an identity permutation) is a special case in this sequence.

Crossrefs

Complement: A275814.
Cf. A275809 (a subsequence).

A275814 Positions of even terms in A060131; indices of permutations of an even order in tables A060117 & A060118.

Original entry on oeis.org

1, 2, 4, 6, 7, 9, 11, 12, 15, 16, 17, 18, 20, 21, 23, 24, 25, 26, 27, 28, 29, 31, 32, 34, 37, 38, 40, 43, 44, 46, 48, 49, 51, 53, 55, 56, 58, 60, 61, 62, 64, 66, 67, 68, 70, 72, 75, 76, 77, 78, 79, 80, 82, 85, 86, 88, 90, 91, 92, 94, 96, 98, 99, 101, 102, 103, 104, 106, 108, 109, 110, 112, 115, 116, 118, 120, 121, 122, 123, 124, 125
Offset: 1

Views

Author

Antti Karttunen, Aug 10 2016

Keywords

Crossrefs

Complement: A275813.
Cf. A275834 (a subsequence).

A275833 Positions of odd terms in A275832; indices of those permutations in tables A060117 & A060118 where element 1 is in an odd cycle.

Original entry on oeis.org

0, 2, 3, 5, 6, 8, 10, 12, 13, 14, 19, 22, 24, 26, 27, 29, 30, 32, 33, 35, 36, 38, 39, 41, 42, 44, 45, 47, 48, 50, 52, 54, 56, 57, 59, 60, 61, 62, 63, 64, 65, 67, 69, 71, 72, 73, 74, 78, 79, 80, 81, 82, 83, 84, 86, 87, 89, 93, 94, 95, 97, 100, 103, 105, 107, 111, 112, 113, 114, 116, 117, 119, 120, 122, 123, 125, 126, 128, 130, 132, 133, 134, 139, 142, 144
Offset: 0

Views

Author

Antti Karttunen, Aug 11 2016

Keywords

Comments

Indexing starts from zero, because a(0)=0 is a special case in this sequence.
Equally: positions of odd terms in A275726.

Crossrefs

Complement: A275834.
Cf. A153880 (a subsequence).

A064039 Reversed inversion vectors for the permutations of A060117, presented as pseudo-decimal numbers.

Original entry on oeis.org

0, 1, 10, 11, 21, 20, 100, 101, 110, 111, 121, 120, 210, 211, 200, 201, 220, 221, 311, 310, 321, 320, 301, 300, 1000, 1001, 1010, 1011, 1021, 1020, 1100, 1101, 1110, 1111, 1121, 1120, 1210, 1211, 1200, 1201, 1220, 1221, 1311, 1310, 1321, 1320, 1301, 1300
Offset: 1

Views

Author

Antti Karttunen, Aug 23 2001

Keywords

Comments

If one uses the ordering of A055089 instead of A060117 (procedure PermRevLexUnrank instead of PermUnrank3R) one gets A007623 (Integers written in factorial base) which is a permutation of this sequence.

Crossrefs

SiteSwap2ToDec procedure given in A060496 and PermUnrank3R in A060117.

Programs

  • Maple
    [seq(SiteSwap2ToDec(Perm2InversionVector(PermUnrank3R(j))),j=0..119)];
    Perm2InversionVector := proc(p) local n,i,j,a,c; n := nops(p); a := []; for i from 2 to n do c := 0; for j from 1 to i-1 do if(p[j] > p[i] then c := c+1; fi; od; a := [op(a),c]; od; RETURN(a); end;

A055089 List of all finite permutations in reversed colexicographic ordering.

Original entry on oeis.org

1, 2, 1, 1, 3, 2, 3, 1, 2, 2, 3, 1, 3, 2, 1, 1, 2, 4, 3, 2, 1, 4, 3, 1, 4, 2, 3, 4, 1, 2, 3, 2, 4, 1, 3, 4, 2, 1, 3, 1, 3, 4, 2, 3, 1, 4, 2, 1, 4, 3, 2, 4, 1, 3, 2, 3, 4, 1, 2, 4, 3, 1, 2, 2, 3, 4, 1, 3, 2, 4, 1, 2, 4, 3, 1, 4, 2, 3, 1, 3, 4, 2, 1, 4, 3, 2, 1, 1, 2, 3, 5, 4, 2, 1, 3, 5, 4, 1, 3, 2, 5, 4, 3, 1, 2
Offset: 0

Views

Author

Antti Karttunen, Apr 18 2000

Keywords

Examples

			In this table, each row consists of A001563(n) permutations of n+1 terms; i.e., we have (1/) 2,1/ 1,3,2; 3,1,2; 2,3,1; 3,2,1/ 1,2,4,3; 2,1,4,3; ... .
Append to each an infinite number of fixed terms and we get a list of rearrangements of the natural numbers, but with only a finite number of terms permuted:
1/2,3,4,5,6,7,8,9,...
2,1/3,4,5,6,7,8,9,...
1,3,2/4,5,6,7,8,9,...
3,1,2/4,5,6,7,8,9,...
2,3,1/4,5,6,7,8,9,...
3,2,1/4,5,6,7,8,9,...
1,2,4,3/5,6,7,8,9,...
2,1,4,3/5,6,7,8,9,...
Alternatively, if we take only the first n terms of each such infinite row, then the first n! rows give all permutations of the elements 1,2,...,n.
		

Crossrefs

Inversion vectors: A007623, cycle counts: A055090, minimum number of transpositions: A055091, minimum number of adjacent transpositions: A034968, order of each permutation: A055092, number of non-fixed elements: A055093, positions of inverses: A056019, positions after Foata transform: A065181; positions of fixed-point-free involutions: A064640.
Cf. A195663, array of the infinite rows.
This permutation list gives essentially the same information as A030298/A030299, but in a more compact way, by skipping those permutations of A030298 that start with a fixed element.
A220658(n) gives the rank r of the permutation of which the term at a(n) is an element.
A220659(n) gives the zero-based position (from the left) of that a(n) in that permutation of rank r.
A084558(r)+1 gives the size of the finite subsequence (of the r-th infinite, but finitary permutation) which has been included in this list.

Programs

  • Maple
    factorial_base := proc(nn) local n,a,d,j,f; n := nn; if(0 = n) then RETURN([0]); fi; a := []; f := 1; j := 2; while(n > 0) do d := floor(`mod`(n,(j*f))/f); a := [d,op(a)]; n := n - (d*f); f := j*f; j := j+1; od; RETURN(a); end;
    fexlist2permlist := proc(a) local n,b,j; n := nops(a); if(0 = n) then RETURN([1]); fi; b := fexlist2permlist(cdr(a)); for j from 1 to n do if(b[j] >= ((n+1)-a[1])) then b[j] := b[j]+1; fi; od; RETURN([op(b),(n+1)-a[1]]); end;
    fac_base := n -> fac_base_aux(n,2); fac_base_aux := proc(n,i) if(0 = n) then RETURN([]); else RETURN([op(fac_base_aux(floor(n/i),i+1)), (n mod i)]); fi; end;
    PermRevLexUnrank := n -> `if`((0 = n),[1],fexlist2permlist(fac_base(n)));
    cdr := proc(l) if 0 = nops(l) then ([]) else (l[2..nops(l)]); fi; end; # "the tail of the list"
    # Same algorithm in different guise, showing how permutations are composed of adjacent transpositions (compare to algorithm PermUnrank3R at A060117):
    PermRevLexUnrankAMSDaux := proc(n,r, pp) local s,p,k; p := pp; if(0 = r) then RETURN(p); else s := floor(r/((n-1)!)); for k from n-s to n-1 do p := permul(p,[[k,k+1]]); od; RETURN(PermRevLexUnrankAMSDaux(n-1, r-(s*((n-1)!)), p)); fi; end;
    PermRevLexUnrankAMSD := proc(r) local n; n := nops(factorial_base(r)); convert(PermRevLexUnrankAMSDaux(n+1,r,[]),'permlist',1+(((r+2) mod (r+1))*n)); end;
  • Mathematica
    A055089L[n_] := Reverse@SortBy[DeleteCases[Permutations@Range@n, {, n}], Reverse]; Flatten@Array[A055089L, 4] (* JungHwan Min, Aug 28 2016 *)

Formula

[seq(op(PermRevLexUnrank(j)), j=0..)]; (see Maple code given below).

Extensions

Name changed by Tilman Piesk, Feb 01 2012

A255411 Shift factorial base representation of n one digit left (with 0 added to right), increment all nonzero digits by one, then convert back to decimal; Numbers with no digit 1 in their factorial base representation.

Original entry on oeis.org

0, 4, 12, 16, 18, 22, 48, 52, 60, 64, 66, 70, 72, 76, 84, 88, 90, 94, 96, 100, 108, 112, 114, 118, 240, 244, 252, 256, 258, 262, 288, 292, 300, 304, 306, 310, 312, 316, 324, 328, 330, 334, 336, 340, 348, 352, 354, 358, 360, 364, 372, 376, 378, 382, 408, 412, 420, 424, 426, 430, 432, 436, 444
Offset: 0

Views

Author

Antti Karttunen, Apr 16 2015

Keywords

Comments

Nonnegative integers such that the number of ones (A257511) in their factorial base representation (A007623) is zero.
Nonnegative integers such that the least missing nonzero digit (A257079) in their factorial base representation is one.
a(n) can be also directly computed from n by "shifting left" its factorial base representation (that is, by appending one zero to the right, see A153880) and then incrementing all nonzero digits by one, and then converting the resulting (still valid) factorial base number back to decimal. See the examples.
The sequences A227130 and A227132 are closed under a(n), in other words, permutation listed as the a(n)-th entry in tables A060117 & A060118 has the same parity as the n-th entry in those same tables.

Examples

			Factorial base representation (A007623) of 1 is "1", shifting it left yields "10", and when we increment all nonzero digits by one, we get "20", which is the factorial base representation of 4 (as 4 = 2*2! + 0*1!), thus a(1) = 4.
F.b.r. of 2 is "10", shifting it left yields "100", and "200" is f.b.r. of 12, thus a(2) = 12.
F.b.r. of 43 is "1301", shifting it left and incrementing all nonzeros by one yields "24020", which is f.b.r of 340, thus a(43) = 340.
		

Crossrefs

Complement: A256450.
Positions of ones in A257079, fixed points of A257080, positions of zeros in A257511, A257081 and A257261.
Cf. also A227130/A227132, A060117/A060118 and also arrays A257503 & A257505.

Programs

  • Mathematica
    factBaseIntDs[n_] := Module[{m, i, len, dList, currDigit}, i = 1; While[n > i!, i++]; m = n; len = i; dList = Table[0, {len}]; Do[currDigit = 0; While[m >= j!, m = m - j!; currDigit++]; dList[[len - j + 1]] = currDigit, {j, i, 1, -1}]; If[dList[[1]] == 0, dList = Drop[dList, 1]]; dList]; s = Table[FromDigits[factBaseIntDs[n]], {n, 500}]; {0}~Join~Flatten@ Position[s, x_ /; DigitCount[x][[1]] == 0](* Michael De Vlieger, Apr 27 2015, after Alonso del Arte at A007623 *)
    Select[Range[0, 444], ! MemberQ[IntegerDigits[#, MixedRadix[Reverse@ Range@ 12]], 1] &] (* Michael De Vlieger, May 30 2016, Version 10.2 *)
    r = MixedRadix[Reverse@Range[2, 12]]; Table[FromDigits[Map[If[# == 0, 0, # + 1] &, IntegerDigits[n, r]]~Join~{0}, r], {n, 0, 60}] (* Michael De Vlieger, Aug 14 2016, Version 10.2 *)
  • Python
    from sympy import factorial as f
    def a007623(n, p=2): return n if n

    0 else '0' for i in x)[::-1] return 0 if n==0 else sum(int(y[i])*f(i + 1) for i in range(len(y))) print([a(n) for n in range(101)]) # Indranil Ghosh, Jun 20 2017

A030299 Decimal representation of permutations of lengths 1, 2, 3, ... arranged lexicographically.

Original entry on oeis.org

1, 12, 21, 123, 132, 213, 231, 312, 321, 1234, 1243, 1324, 1342, 1423, 1432, 2134, 2143, 2314, 2341, 2413, 2431, 3124, 3142, 3214, 3241, 3412, 3421, 4123, 4132, 4213, 4231, 4312, 4321, 12345, 12354, 12435, 12453, 12534, 12543, 13245, 13254, 13425
Offset: 1

Views

Author

Keywords

Comments

This is a list of the permutations in "one-line" notation (cf. Dixon and Mortimer, p. 2). The i-th element of the string is the image of i under the permutation. For example 231 is the permutation that sends 1 to 2, 2 to 3, and 3 to 1. - N. J. A. Sloane, Apr 12 2014
Precise definition of the term "Decimal representation" (required for indices n>409113): Numbers N(s) = Sum_{i=1..m} s(i)*10^(m-i), where s runs over the permutations of (1,...,m), and m=1,2,3,.... This also defines the "lexicographical" order: Obviously 21 comes before 123, etc. The lexicographical order of the permutations, for given m, is the same as the natural order of the numbers N(s). - M. F. Hasler, Jan 28 2013
An alternate variant, using concatenation of the permutations, is very clumsy once the length exceeds 9. For example, after 987654321 (= A030299(409113), where 409113 = A007489(9)) we would get 12345678910, 12345678109, ... In A030298 this problem has been avoided by listing the elements of permutations as separate terms. [Edited by M. F. Hasler, Jan 28 2013]
Sequence A051845 is a base-independent version of this sequence: Permutations of 1...m are considered as numbers written in base m+1. - M. F. Hasler, Jan 28 2013

References

  • John D. Dixon and Brian Mortimer, Permutation groups. Graduate Texts in Mathematics, 163. Springer-Verlag, New York, 1996. xii+346 pp. ISBN: 0-387-94599-7 MR1409812 (98m:20003).

Crossrefs

A007489(n) gives the position (index) of the term corresponding to last permutation of n elements: (n,n-1,...,1).
The first differences A220664 has interesting fractal structure, see A219664 and A217626.
Cf. also A030298, A055089, A060117, A181073, A352991 (by concatenation).
See A240763 for preferential arrangements.

Programs

  • Maple
    seq(seq(add(s[i]*10^(m-i),i=1..m),s=combinat:-permute([$1..m])),m=1..5); # Robert Israel, Oct 14 2015
  • Mathematica
    Flatten @ Table[FromDigits /@ Permutations[Table[i,{i,n}]],{n,9}] (* For first 409113 terms; Zak Seidov, Oct 03 2015 *)
  • PARI
    is_A030299(n)={ (n>1234567890 & print("maybe")) || vecsort(digits(n))==vector(#Str(n),i,i) } \\ /* use digits(n)=eval(Vec(Str(n))) in older versions lacking this function */ \\ M. F. Hasler, Dec 12 2012
    (MIT/GNU Scheme)
    ;; Antti Karttunen, Dec 18 2012
    ;; Requires also code from A030298 and A055089:
    (define (A030299 n) (vector->base-k (A030298permvec (A084556 n) (A220660 n)) 10))
    (define (vector->base-k vec k) (let loop ((i 0) (s 0)) (cond ((= (vector-length vec) i) s) ((>= (vector-ref vec i) k) (error (format #f "Cannot interpret vector ~a in base ~a!" vec k))) (else (loop (+ i 1) (+ (* k s) (vector-ref vec i)))))))
    
  • Python
    from itertools import permutations
    def pmap(s, m): return sum(s[i-1]*10**(m-i) for i in range(1, len(s)+1))
    def agen():
      m = 1
      while True:
        for s in permutations(range(1, m+1)): yield pmap(s, m)
        m += 1
    def aupton(terms):
      alst, g = [], agen()
      while len(alst) < terms: alst += [next(g)]
      return alst
    print(aupton(42)) # Michael S. Branicky, Jan 12 2021

Extensions

Edited by N. J. A. Sloane, Feb 23 2010
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