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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A261217 A(i,j) = rank (in A060118) of the composition of the i-th and the j-th permutation in table A060118, which lists all finite permutations.

Original entry on oeis.org

0, 1, 1, 2, 0, 2, 3, 3, 5, 3, 4, 2, 0, 4, 4, 5, 5, 4, 1, 3, 5, 6, 4, 3, 5, 5, 2, 6, 7, 7, 1, 2, 1, 4, 7, 7, 8, 6, 8, 0, 0, 0, 14, 6, 8, 9, 9, 11, 9, 2, 1, 15, 15, 11, 9, 10, 8, 6, 10, 10, 3, 22, 14, 12, 10, 10, 11, 11, 10, 7, 9, 11, 23, 23, 16, 13, 9, 11, 12, 10, 9, 11, 11, 8, 0, 22, 21, 17, 17, 8, 12, 13, 13, 7, 8, 7, 10, 1, 1, 19, 20, 13, 16, 19, 13, 14, 12, 14, 6, 6, 6, 12, 0, 2, 18, 18, 12, 8, 18, 14
Offset: 0

Views

Author

Antti Karttunen, Aug 26 2015

Keywords

Comments

The square array A(row>=0, col>=0) is read by downwards antidiagonals as: A(0,0), A(0,1), A(1,0), A(0,2), A(1,1), A(2,0), A(0,3), A(1,2), A(2,1), A(3,0), ...
A(i,j) gives the rank (in ordering used by table A060118) of the permutation which is obtained by composing permutations p and q listed as the i-th and the j-th permutation in irregular table A060118 (note that the identity permutation is the 0th). Here the convention is that "permutations act of the left", thus, if p1 and p2 are permutations, then the product of p1 and p2 (p1 * p2) is defined such that (p1 * p2)(i) = p1(p2(i)) for i=1...
Equally, A(i,j) gives the rank in A060117 of the composition of the i-th and the j-th permutation in A060117, when convention is that "permutations act on the right".
Each row and column is a permutation of A001477, because this is the Cayley table ("multiplication table") of an infinite enumerable group, namely, that subgroup of the infinite symmetric group (S_inf) which consists of permutations moving only finite number of elements.

Examples

			The top left corner of the array:
   0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, ...
   1,  0,  3,  2,  5,  4,  7,  6,  9,  8, 11, 10, 13, ...
   2,  5,  0,  4,  3,  1,  8, 11,  6, 10,  9,  7, 14, ...
   3,  4,  1,  5,  2,  0,  9, 10,  7, 11,  8,  6, 15, ...
   4,  3,  5,  1,  0,  2, 10,  9, 11,  7,  6,  8, 16, ...
   5,  2,  4,  0,  1,  3, 11,  8, 10,  6,  7,  9, 17, ...
   6,  7, 14, 15, 22, 23,  0,  1, 12, 13, 18, 19,  8, ...
   7,  6, 15, 14, 23, 22,  1,  0, 13, 12, 19, 18,  9, ...
   8, 11, 12, 16, 21, 19,  2,  5, 14, 17, 20, 23,  6, ...
   9, 10, 13, 17, 20, 18,  3,  4, 15, 16, 21, 22,  7, ...
  10,  9, 17, 13, 18, 20,  4,  3, 16, 15, 22, 21, 11, ...
  11,  8, 16, 12, 19, 21,  5,  2, 17, 14, 23, 20, 10, ...
  12, 19,  8, 21, 16, 11, 14, 23,  2, 20, 17,  5,  0, ...
  ...
For A(1,2) (row=1, column=2, both starting from zero), we take as permutation p the permutation which has rank=1 in the ordering used by A060118, which is a simple transposition (1 2), which we can extend with fixed terms as far as we wish (e.g., like {2,1,3,4,5,...}), and as permutation q we take the permutation which has rank=2 (in the same list), which is {1,3,2}. We compose these from the left, so that the latter one, q, acts first, thus c(i) = p(q(i)), and the result is permutation {2,3,1}, which is listed as the 3rd one in A060118, thus A(1,2) = 3.
For A(2,1) we compose those two permutations in opposite order, as d(i) = q(p(i)), which gives permutation {3,1,2} which is listed as the 5th one in A060118, thus A(2,1) = 5.
		

Crossrefs

Transpose: A261216.
Row 0 & Column 0: A001477 (identity permutation)
Row 1: A004442.
Column 1: A261218.
Main diagonal: A261219.
Cf. also A089839.
Permutations used in conjugation-formulas: A060119, A060120, A060125, A060126, A060127.

Formula

By conjugating with related permutations and arrays:
A(i,j) = A060125(A261216(A060125(i),A060125(j))).
A(i,j) = A060127(A261096(A060120(i),A060120(j))).
A(i,j) = A060126(A261097(A060119(i),A060119(j))).

A178476 Permutations of 123456: Numbers having each of the decimal digits 1,...,6 exactly once, and no other digit.

Original entry on oeis.org

123456, 123465, 123546, 123564, 123645, 123654, 124356, 124365, 124536, 124563, 124635, 124653, 125346, 125364, 125436, 125463, 125634, 125643, 126345, 126354, 126435, 126453, 126534, 126543, 132456, 132465, 132546, 132564, 132645, 132654
Offset: 1

Views

Author

M. F. Hasler, May 28 2010

Keywords

Comments

This finite sequence contains 6!=720 terms.
This is a subsequence of A030299, consisting of elements A030299(154)..A030299(873).
If individual digits are be split up into separate terms, we get a subsequence of A030298.
It would be interesting to conceive simple and/or efficient functions which yield (a) the n-th term of this sequence: f(n)=a(n), (b) for a given term, the subsequent one: f(a(n)) = a(1 + (n mod 6!)).
The expression a(n+6) - a(n) takes only 18 different values for n = 1..6!-6.
An efficient procedure for generating the n-th term of this sequence can be found at A178475. - Nathaniel Johnston, May 19 2011
From Hieronymus Fischer, Feb 13 2013: (Start)
The sum of all terms as decimal numbers is 279999720.
General formula for the sum of all terms (interpreted as decimal permutational numbers with exactly d different digits from the range 1..d < 10): sum = (d+1)!*(10^d-1)/18.
If the terms are interpreted as base-7 numbers the sum is 49412160.
General formula for the sum of all terms of the corresponding sequence of base-p permutational numbers (numbers with exactly p-1 different digits excluding the zero digit): sum = (p-2)!*(p^p-p)/2. (End)

Crossrefs

Programs

  • Mathematica
    Take[FromDigits/@Permutations[Range[6]],40] (* Harvey P. Dale, Jun 05 2012 *)
  • PARI
    v=vector(6,i,10^(i-1))~; A178476=vecsort(vector(6!,i,numtoperm(6,i)*v));
    is_A178476(x)= { vecsort(Vec(Str(x)))==Vec("123456") }
    forstep( m=123456,654321,9, is_A178476(m) & print1(m","))

Formula

a(n) + a(6! + 1 - n) = 777777.
floor( a(n) / 10^5 ) = ceiling( n / 5! ).
a(n) = A030299(n+153).
a(n) == 3 (mod 9).
a(n) = 3 + 9*A178486(n).

A178485 (A178475(n)-6)/9.

Original entry on oeis.org

1371, 1372, 1381, 1383, 1392, 1393, 1471, 1472, 1491, 1494, 1502, 1504, 1581, 1583, 1591, 1594, 1613, 1614, 1692, 1693, 1702, 1704, 1713, 1714, 2371, 2372, 2381, 2383, 2392, 2393, 2571, 2572, 2601, 2605, 2612, 2615, 2681, 2683, 2701, 2705, 2723, 2725
Offset: 1

Views

Author

M. F. Hasler, May 28 2010

Keywords

Comments

There are 5!=120 terms in this finite sequence. Its origin is the fact that numbers whose decimal expansion is a permutation of 12345 are all of the form 9k+6.

Crossrefs

Programs

  • PARI
    v=vector(5,i,10^(i-1))~; vecsort(vector(5!,i,numtoperm(5,i)*v))
    is_A178475(x)= { vecsort(Vec(Str(x)))==Vec("12345") }
    forstep( m=12345,54321,9, is_A178475(m) & print1(m","))

Formula

a(n) + a(5!+1-n) = 7406.
a(n) == 1, 2, 3, 4 or 5 (mod 10).
a(n+6)-a(n) is an element of { 100, 110, 111, 200, 220, 222, 679 }.
a(n+6)-a(n) = 679 iff (n-1)%24 > 17, where % denotes the remainder upon division.
a(n+6)-a(n) = 200, 220 or 222 iff (n-1)%30 > 23, i.e. n==25,...,30 (mod 30).

A178486 (A178476(n)-3)/9.

Original entry on oeis.org

13717, 13718, 13727, 13729, 13738, 13739, 13817, 13818, 13837, 13840, 13848, 13850, 13927, 13929, 13937, 13940, 13959, 13960, 14038, 14039, 14048, 14050, 14059, 14060, 14717, 14718, 14727, 14729, 14738, 14739, 14917, 14918, 14947, 14951, 14958, 14961
Offset: 1

Views

Author

M. F. Hasler, May 28 2010

Keywords

Comments

The sequence is motivated by the fact that numbers whose decimal expansion is a permutation of 123456, are all of the form 9k+3.
There are 6!=720 terms in this finite sequence.

Crossrefs

Programs

  • PARI
    forstep( m=123456,654321/*or less*/,9, is_A178476(m) & print1(m\9",")) /*cf. A178476*/

Formula

a(n) + a(6!+1-n) = 86419.
a(n) == 0, 1, 2, 7, 8 or 9 (mod 10).

A220658 Irregular table, where the n-th row consists of A084558(n)+1 copies of n.

Original entry on oeis.org

0, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 9, 9, 9, 9, 10, 10, 10, 10, 11, 11, 11, 11, 12, 12, 12, 12, 13, 13, 13, 13, 14, 14, 14, 14, 15, 15, 15, 15, 16, 16, 16, 16, 17, 17, 17, 17, 18, 18, 18, 18, 19, 19, 19, 19, 20, 20
Offset: 0

Views

Author

Antti Karttunen, Dec 18 2012

Keywords

Comments

Equally, for n>=1, each i in range [n!,(n+1)!-1] occurs n+1 times.
Used for computing A220659, A055089 and A060118: The n-th term a(n) tells which permutation (counted from the start, zero-based) of A055089 or A060117/A060118 the n-th term in those sequence belongs to.

Examples

			Rows of this irregular table begin as:
0;
1, 1;
2, 2, 2;
3, 3, 3;
4, 4, 4;
5, 5, 5;
6, 6, 6, 6;
The terms A055089(3), A055089(4) and A055089(5) are 1,3,2. As a(3), a(4) and a(5) are all 2, we see that "132" is the second permutation in A055089-list, after the identity permutation "1", which has the index zero.
		

Crossrefs

A220659 Irregular table: row n (n >= 1) consists of numbers 0..A084558(n).

Original entry on oeis.org

0, 0, 1, 0, 1, 2, 0, 1, 2, 0, 1, 2, 0, 1, 2, 0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3
Offset: 0

Views

Author

Antti Karttunen, Dec 18 2012

Keywords

Comments

The term a(n) gives the position (zero-based, starting from the left hand end of permutation) of a corresponding permutation A055089 and A060117/A060118 from which the term A055089(n) or A060118(n) is to be picked.

Examples

			Rows of this irregular table begin as:
0;
0, 1;
0, 1, 2;
0, 1, 2;
0, 1, 2;
0, 1, 2;
0, 1, 2, 3;
The term 2 occurs four times in A084558, in positions 2, 3, 4 and 5. Thus rows 2, 3, 4 and 5 (zero-based) of this irregular table are all 0,1,2.
		

Programs

Formula

a(n) = n - A220657(A220658(n)).

A060500 a(n) = number of drops in the n-th permutation of list A060118; the average of digits (where "digits" may eventually obtain also any values > 9) in each siteswap pattern A060496(n).

Original entry on oeis.org

0, 1, 1, 1, 1, 2, 1, 2, 1, 1, 1, 2, 1, 1, 2, 2, 2, 2, 1, 2, 2, 2, 2, 3, 1, 2, 2, 2, 2, 3, 1, 2, 1, 1, 1, 2, 1, 1, 2, 2, 2, 2, 1, 2, 2, 2, 2, 3, 1, 2, 1, 1, 1, 2, 2, 3, 2, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 3, 2, 2, 2, 3, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 2, 2, 3, 3, 3, 3, 1, 2, 2, 2, 2, 3, 2, 3, 2
Offset: 0

Views

Author

Antti Karttunen, Mar 22 2001

Keywords

Crossrefs

Programs

  • Maple
    A060500 := avg(Perm2SiteSwap1(PermUnrank3R(n)));
    # PermUnrank3R(r) gives the permutation with rank r in list A060117:
    PermUnrank3R := proc(r) local n; n := nops(factorial_base(r)); convert(PermUnrank3Raux(n+1, r, []), 'permlist', 1+(((r+2) mod (r+1))*n)); end;
    PermUnrank3Raux := proc(n, r, p) local s; if(0 = r) then RETURN(p); else s := floor(r/((n-1)!)); RETURN(PermUnrank3Raux(n-1, r-(s*((n-1)!)), permul(p, [[n, n-s]]))); fi; end;
    Perm2SiteSwap1 := proc(p) local ip, n, i, a; n := nops(p); ip := convert(invperm(convert(p, 'disjcyc')), 'permlist', n); a := []; for i from 1 to n do a := [op(a), ((ip[i]-i) mod n)]; od; RETURN(a); end;
    avg := a -> (convert(a,`+`)/nops(a));
  • Scheme
    (define (A060500 n) (let ((s (+ 1 (A084558 n))) (p (A060118permvec-short n))) (let loop ((d 0) (i 1)) (if (> i s) d (loop (+ d (if (< (vector-ref p (- i 1)) i) 1 0)) (+ 1 i))))))
    (define (A060118permvec-short rank) (permute-A060118 (make-initialized-vector (+ 1 (A084558 rank)) 1+) (+ 1 (A084558 rank)) rank))
    (define (permute-A060118 elems size permrank) (let ((p (vector-head elems size))) (let unrankA060118 ((r permrank) (i 1)) (cond ((zero? r) p) (else (let* ((j (1+ i)) (m (modulo r j))) (cond ((not (zero? m)) (let ((org-i (vector-ref p i))) (vector-set! p i (vector-ref p (- i m))) (vector-set! p (- i m) org-i)))) (unrankA060118 (/ (- r m) j) j)))))))

Formula

From Antti Karttunen, Aug 18 2016: (Start)
The following formula reflects the original definition of computing the average, with a few unnecessary steps eliminated:
a(n) = 1/s * Sum_{i=1..s} ((i-p[i]) modulo s), where p is the permutation of rank n as ordered in the list A060117, and s is its size (the number of its elements) computed as s = 1+A084558(n).
a(n) = 1/s * Sum_{i=1..s} ((p[i]-i) modulo s). [If inverse permutations from list A060118 are used, then we just flip the order of difference that is used in the first formula].
a(n) = Sum_{i=1..s} [p[i]A060502 for the proof].
a(n) = A060502(A060125(n)).
a(n) = A060129(n) - A060502(n).
a(n) = A060501(n) - A275851(n) = 1 + A275849(n) - A275851(n).
(End)

Extensions

Maple code collected together, alternative definition and new formulas added by Antti Karttunen, Aug 24 2016

A178477 Permutations of 1234567: Numbers having each of the decimal digits 1,...,7 exactly once, and no other digit.

Original entry on oeis.org

1234567, 1234576, 1234657, 1234675, 1234756, 1234765, 1235467, 1235476, 1235647, 1235674, 1235746, 1235764, 1236457, 1236475, 1236547, 1236574, 1236745, 1236754, 1237456, 1237465, 1237546, 1237564, 1237645, 1237654
Offset: 1

Views

Author

M. F. Hasler, Oct 09 2010

Keywords

Comments

It would be nice to have a simple explicit formula for the n-th term.
Contains A000142(7) = 5040 terms. - R. J. Mathar, Apr 08 2011
An efficient procedure for generating the n-th term of this sequence can be found at A178475. - Nathaniel Johnston, May 19 2011

Crossrefs

Programs

  • Mathematica
    FromDigits/@Take[Permutations[Range[7]],50] (* Harvey P. Dale, Nov 11 2012 *)
  • PARI
    is_A178477(x)= { vecsort(Vec(Str(x)))==Vec("1234567") }

A178478 Permutations of 12345678: Numbers having each of the decimal digits 1..8 exactly once, and no other digit.

Original entry on oeis.org

12345678, 12345687, 12345768, 12345786, 12345867, 12345876, 12346578, 12346587, 12346758, 12346785, 12346857, 12346875, 12347568, 12347586, 12347658, 12347685, 12347856, 12347865, 12348567, 12348576, 12348657, 12348675, 12348756, 12348765
Offset: 1

Views

Author

M. F. Hasler, Oct 09 2010

Keywords

Comments

It would be nice to have a simple explicit formula for the n-th term.
An efficient procedure for generating the n-th term of this sequence can be found at A178475. - Nathaniel Johnston, May 19 2011

Crossrefs

Programs

  • Mathematica
    Take[FromDigits/@Permutations[Range[8]],40] (* Harvey P. Dale, Oct 29 2014 *)
  • PARI
    is_A178478(x)= { vecsort(Vec(Str(x)))==Vec("12345678") }
    
  • PARI
    A178478(n)={my(b=vector(7,k,1+(n-1)%(k+1)!\k!),t=b[7], d=vector(7,i,i+(i>=t)));for(i=1,6,t=10*t+d[b[7-i]]; d=vecextract(d,Str("^"b[7-i]))); t*10+d[1]} \\ - M. F. Hasler (following N. Johnston's comment), Jan 10 2012

A261218 Row 1 of A261216.

Original entry on oeis.org

1, 0, 5, 4, 3, 2, 7, 6, 11, 10, 9, 8, 19, 18, 23, 22, 21, 20, 13, 12, 17, 16, 15, 14, 25, 24, 29, 28, 27, 26, 31, 30, 35, 34, 33, 32, 43, 42, 47, 46, 45, 44, 37, 36, 41, 40, 39, 38, 49, 48, 53, 52, 51, 50, 55, 54, 59, 58, 57, 56, 67, 66, 71, 70, 69, 68, 61, 60, 65, 64, 63, 62, 97, 96, 101, 100, 99, 98, 103, 102, 107, 106, 105, 104, 115, 114, 119, 118, 117, 116, 109, 108, 113, 112, 111, 110, 73
Offset: 0

Views

Author

Antti Karttunen, Aug 26 2015

Keywords

Comments

Equally, column 1 of A261217.
Take the n-th (n>=0) permutation from the list A060117, change 1 to 2 and 2 to 1 to get another permutation, and note its rank in the same list to obtain a(n).
Equally, we can take the n-th (n>=0) permutation from the list A060118, swap the elements in its two leftmost positions, and note the rank of that permutation in A060118 to obtain a(n).
Self-inverse permutation of nonnegative integers.

Examples

			In A060117 the permutation with rank 2 is [1,3,2], and swapping the elements 1 and 2 we get permutation [2,3,1], which is listed in A060117 as the permutation with rank 5, thus a(2) = 5.
Equally, in A060118 the permutation with rank 2 is [1,3,2], and swapping the elements in the first and the second position gives permutation [3,1,2], which is listed in A060118 as the permutation with rank 5, thus a(2) = 5.
		

Crossrefs

Row 1 of A261216, column 1 of A261217.
Cf. also A004442.
Related permutations: A060119, A060126, A261098.

Formula

a(n) = A261216(1,n).
By conjugating related permutations:
a(n) = A060126(A261098(A060119(n))).
Previous Showing 41-50 of 54 results. Next