A054119 -id:A054119 - cp's OEIS frontend

A276955 Square array A(row,col): A(row,1) = A273670(row-1), and for col > 1, A(row,col) = A153880(A(row,col-1)); Dispersion of factorial base left shift A153880.

1, 2, 3, 6, 8, 4, 24, 30, 12, 5, 120, 144, 48, 14, 7, 720, 840, 240, 54, 26, 9, 5040, 5760, 1440, 264, 126, 32, 10, 40320, 45360, 10080, 1560, 744, 150, 36, 11, 362880, 403200, 80640, 10800, 5160, 864, 168, 38, 13, 3628800, 3991680, 725760, 85680, 41040, 5880, 960, 174, 50, 15, 39916800, 43545600, 7257600, 766080, 367920, 46080, 6480, 984, 246, 56, 16

Offset: 1

Antti Karttunen, Sep 22 2016

The square array A(row,col) is read by descending antidiagonals: A(1,1), A(1,2), A(2,1), A(1,3), A(2,2), A(3,1), etc.

When viewed in factorial base (A007623) the terms on each row start all with the same prefix, but with an increasing number of zeros appended to the end. For example, for row 8 (A001344 from a(1)=11 onward), the terms written in factorial base look as: 121, 1210, 12100, 121000, ...

			The top left {1..9} x {1..18} corner of the array:
   1,  2,   6,   24,   120,    720,    5040,    40320,    362880
   3,  8,  30,  144,   840,   5760,   45360,   403200,   3991680
   4, 12,  48,  240,  1440,  10080,   80640,   725760,   7257600
   5, 14,  54,  264,  1560,  10800,   85680,   766080,   7620480
   7, 26, 126,  744,  5160,  41040,  367920,  3669120,  40279680
   9, 32, 150,  864,  5880,  46080,  408240,  4032000,  43908480
  10, 36, 168,  960,  6480,  50400,  443520,  4354560,  47174400
  11, 38, 174,  984,  6600,  51120,  448560,  4394880,  47537280
  13, 50, 246, 1464, 10200,  81360,  730800,  7297920,  80196480
  15, 56, 270, 1584, 10920,  86400,  771120,  7660800,  83825280
  16, 60, 288, 1680, 11520,  90720,  806400,  7983360,  87091200
  17, 62, 294, 1704, 11640,  91440,  811440,  8023680,  87454080
  18, 72, 360, 2160, 15120, 120960, 1088640, 10886400, 119750400
  19, 74, 366, 2184, 15240, 121680, 1093680, 10926720, 120113280
  20, 78, 384, 2280, 15840, 126000, 1128960, 11249280, 123379200
  21, 80, 390, 2304, 15960, 126720, 1134000, 11289600, 123742080
  22, 84, 408, 2400, 16560, 131040, 1169280, 11612160, 127008000
  23, 86, 414, 2424, 16680, 131760, 1174320, 11652480, 127370880

Inverse permutation: A276956.
Transpose: A276953.
Cf. A276949 (index of column where n appears), A276951 (index of row).
Cf. A153880.
Columns 1-3: A273670, A276932, A276933.
The following lists some of the rows that have their own entries. Pattern present in the factorial base expansion of the terms on that row is given in double quotes:
Row 1: A000142 (from a(1)=1, "1" onward),
Row 2: A001048 (from a(2)=3, "11" onward),
Row 3: A052849 (from a(2)=4, "20" onward).
Row 4: A052649 (from a(1)=5, "21" onward).
Row 5: A108217 (from a(3)=7, "101" onward).
Row 6: A054119 (from a(3)=9, "111" onward).
Row 7: A052572 (from a(2)=10, "120" onward).
Row 8: A001344 (from a(1)=11, "121" onward).
Row 13: A052560 (from a(3)=18, "300" onward).
Row 16: A225658 (from a(1)=21, "311" onward).
Row 20: A276940 (from a(3) = 27, "1011" onward).
Related or similar permutations: A257505, A275848, A273666.
Cf. also arrays A276617, A276588 & A276945.

(define (A276955 n) (A276955bi (A002260 n) (A004736 n)))
(define (A276955bi row col) (if (= 1 col) (A273670 (- row 1)) (A153880 (A276955bi row (- col 1)))))

A(row,1) = A273670(row-1), and for col > 1, A(row,col) = A153880(A(row,col-1))
As a composition of other permutations:
a(n) = A275848(A257505(n)).

A376269 a(n) = n! + (n - 1)! + (n - 2)! + n - 3.

Original entry on oeis.org

3, 9, 33, 152, 867, 5884, 46085, 408246, 4032007, 43908488, 522547209, 6745939210, 93884313611, 1401079680012, 22317642547213, 377917892352014, 6778983923712015, 128403161542656016, 2560949482291200017, 53645489280294912018, 1177524571957493760019, 27027108408834293760020

Offset: 2

Paolo Xausa, Sep 18 2024

a(n) is a lower bound for the length of every superpermutation on n symbols (see links). An upper bound for the length of a minimal superpermutation is given by A341300(n).

Paolo Xausa, Table of n, a(n) for n = 2..400
Anonymous 4chan poster, Robin Houston, Jay Pantone, and Vince Vatter, A lower bound on the length of the shortest superpattern, 2018.
Michael Engen and Vincent Vatter, Containing All Permutations, The American Mathematical Monthly, 128 (1), 2021, pp. 4-24 (preprint version).
James Grime and Brady Haran, Superpermutations, Numberphile video, 2018.
Wikipedia, Superpermutation.

Cf. A054119, A180632, A332089, A341300.

Table[n^2 * (n - 2)! + n - 3, {n, 2, 25}]

from sympy import factorial
def A376269(n): return n**2*factorial(n-2)+n-3 # Chai Wah Wu, Sep 20 2024

a(n) = A054119(n) + n - 3.
E.g.f.: (3 - x - x^2 - exp(x)*(3 - 4*x + x^2) - (1 - x)*x*log(1 - x))/(1 - x). - Stefano Spezia, Sep 18 2024
a(n) = (n-2)!*n^2 + n - 3. - Chai Wah Wu, Sep 20 2024
D-finite with recurrence (-n+1)*a(n) +(n-2)*(n+2)*a(n-1) -(n-1)*(n-3)*a(n-2) -(4*n-7)*(n-4)=0. - R. J. Mathar, Sep 23 2024

A276940 a(1) = 2; for n > 1, a(n) = (n-2)! * n^3.

Original entry on oeis.org

2, 8, 27, 128, 750, 5184, 41160, 368640, 3674160, 40320000, 482993280, 6270566400, 87697209600, 1314380390400, 21016195200000, 357082280755200, 6424604169984000, 122021710626816000, 2439660069310464000, 51218989645824000000, 1126555274886193152000, 25905540583064862720000, 621623493403188756480000, 15538186060797648568320000

Offset: 1

Antti Karttunen, Sep 24 2016

In factorial base representation (A007623) the terms are written as: 10, 110, 1011, 10110, 101100, 1011000, 10110000, ... From a(3) = 27 = "1011" onward each term begins always with "1011", followed by n-3 zeros. - Antti Karttunen, Sep 24 2016

Index entries for sequences related to factorial base representation

Cf. A000142, A000578, A054119.

Row 20 of A276955 (from a(3) = 27 onward).

Join[{2},Table[(n-2)! n^3,{n,2,30}]] (* Harvey P. Dale, Apr 14 2017 *)

a(1) = 2; for n > 1, a(n) = (n-2)! * n^3.
a(n) = n * A054119(n).
For n >= 3, a(n) = (n+1)! + (n-1)! + (n-2)!.

A306770 Decimal expansion of Sum_{k>=0} 1/(k! + (k+1)! + (k+2)!).

Original entry on oeis.org

4, 0, 0, 3, 7, 9, 6, 7, 7, 0, 0, 4, 6, 4, 1, 3, 4, 0, 5, 0, 0, 2, 7, 8, 6, 2, 7, 1, 0, 3, 4, 3, 0, 6, 5, 9, 7, 8, 2, 3, 4, 5, 8, 4, 7, 9, 0, 7, 1, 7, 5, 5, 8, 2, 1, 2, 6, 5, 0, 6, 4, 3, 0, 7, 2, 6, 4, 3, 0, 5, 2, 2, 5, 9, 7, 4, 0, 8, 1, 1, 1, 9, 5, 9, 4, 2, 8, 5, 3, 1

Offset: 0

Seiichi Manyama, Mar 09 2019

			0.40037967700464134050027...

Eric Weisstein's World of Mathematics, Exponential Integral.

Cf. A001113 (exp(1)), A001620 (gamma), A054119, A091725 (ExpIntegralEi[1]).

exp(1) - 1 + Euler - real(-eint1(-1)) \\ Michel Marcus, Mar 09 2019

Sum_{k>=0} 1/(k! + (k+1)! + (k+2)!) = exp(1) - 1 + gamma - ExpIntegralEi[1].
From Amiram Eldar, Jun 26 2021: (Start)
Equals Sum_{k>=2} 1/A054119(k).
Equals -Integral{x=0..1} x*log(x)*exp(x) dx. (End)

cp's OEIS Frontend

A276955 Square array A(row,col): A(row,1) = A273670(row-1), and for col > 1, A(row,col) = A153880(A(row,col-1)); Dispersion of factorial base left shift A153880.

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A376269 a(n) = n! + (n - 1)! + (n - 2)! + n - 3.

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A276940 a(1) = 2; for n > 1, a(n) = (n-2)! * n^3.

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A306770 Decimal expansion of Sum_{k>=0} 1/(k! + (k+1)! + (k+2)!).

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