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.

Previous Showing 11-20 of 24 results. Next

A135805 Eighth column (k=7) of triangle A134832 (circular succession numbers).

Original entry on oeis.org

1, 0, 0, 120, 330, 6336, 61776, 785928, 10456875, 151099520, 2339361024, 38655753552, 678721170036, 12615988058880, 247449420044640, 5106608041235184, 110596074738524661, 2507849090860975488
Offset: 0

Views

Author

Wolfdieter Lang, Jan 21 2008

Keywords

Comments

a(n) enumerates circular permutations of {1,2,...,n+7} with exactly seven successor pairs (i,i+1). Due to cyclicity also (n+7,1) is a successor pair.

Examples

			a(0)=1 because from the 7!/7 = 720 circular permutations of n=7 elements only one, namely (1,2,3,4,5,6,7), has seven successors.
		

References

  • Ch. A. Charalambides, Enumerative Combinatorics, Chapman & Hall/CRC, Boca Raton, Florida, 2002, p. 183, eq. (5.15), for k=7.

Crossrefs

Cf. A135804 (column k=6), A135806 (column k=8).

Programs

  • Mathematica
    f[n_] := (-1)^n + Sum[(-1)^k*n!/((n - k)*k!), {k, 0, n - 1}]; a[n_, n_] = 1; a[n_, 0] := f[n]; a[n_, k_] := a[n, k] = n/k*a[n - 1, k - 1]; Table[a[n, 7], {n, 7, 25}] (* G. C. Greubel, Nov 10 2016 *)

Formula

a(n) = binomial(n+7,7)*A000757(n), n>=0.
E.g.f.: (d^7/dx^7) (x^7/7!)*(1-log(1-x))/e^x.

A135806 Ninth column (k=8) of triangle A134832 (circular succession numbers).

Original entry on oeis.org

1, 0, 0, 165, 495, 10296, 108108, 1473615, 20913750, 321086480, 5263562304, 91807414686, 1696802925090, 33116968654560, 680485905122760, 14681498118551154, 331788224215573983, 7837028408940548400
Offset: 0

Views

Author

Wolfdieter Lang, Jan 21 2008

Keywords

Comments

a(n) enumerates circular permutations of {1,2,...,n+8} with exactly eight successor pairs (i,i+1). Due to cyclicity also (n+8,1) is a successor pair.

Examples

			a(0)=1 because from the 8!/8 = 5040 circular permutations of n=8 elements only one, namely (1,2,3,4,5,6,7,8), has eight successors.
		

References

  • Ch. A. Charalambides, Enumerative Combinatorics, Chapman & Hall/CRC, Boca Raton, Florida, 2002, p. 183, eq. (5.15), for k=8.

Crossrefs

Cf. A135805 (column k=7), A135807 (column k=9).

Programs

  • Mathematica
    f[n_] := (-1)^n + Sum[(-1)^k*n!/((n - k)*k!), {k, 0, n - 1}]; a[n_, n_] = 1; a[n_, 0] := f[n]; a[n_, k_] := a[n, k] = n/k*a[n - 1, k - 1]; Table[a[n, 8], {n, 8, 25}] (* G. C. Greubel, Nov 10 2016 *)

Formula

a(n) = binomial(n+8,8)*A000757(n), n>=0.
E.g.f.: (d^8/dx^8) (x^8/8!)*(1-log(1-x))/e^x.

A027765 a(n) = (n+1)*binomial(n+1,5).

Original entry on oeis.org

5, 36, 147, 448, 1134, 2520, 5082, 9504, 16731, 28028, 45045, 69888, 105196, 154224, 220932, 310080, 427329, 579348, 773927, 1020096, 1328250, 1710280, 2179710, 2751840, 3443895, 4275180, 5267241, 6444032, 7832088, 9460704, 11362120, 13571712, 16128189
Offset: 4

Views

Author

Thi Ngoc Dinh (via R. K. Guy)

Keywords

Comments

Number of 7-subsequences of [ 1, n ] with just 1 contiguous pair.
8*a(n) is the number of permutations of (n+1) symbols that 5-commute with an (n+1)-cycle (see A233440 for definition), where 8 = A000757(5). - Luis Manuel Rivera Martínez, Feb 07 2014

Crossrefs

Programs

  • Magma
    [(n+1)*Binomial(n+1,5): n in [4..40]]; // Vincenzo Librandi, Aug 09 2017
  • Maple
    a:=n->(sum((numbcomp(n,6)), j=2..n)):seq(a(n), n=6..34); # Zerinvary Lajos, Aug 26 2008
  • Mathematica
    Table[(n+1)Binomial[n+1,5],{n,4,40}] (* or *) LinearRecurrence[{7,-21,35,-35,21,-7,1},{5,36,147,448,1134,2520,5082},40] (* Harvey P. Dale, Jan 15 2017 *)

Formula

G.f.: (5+x)*x^4/(1-x)^7.
From Amiram Eldar, Jan 30 2022: (Start)
Sum_{n>=4} 1/a(n) = 5*Pi^2/6 - 575/72.
Sum_{n>=4} (-1)^n/a(n) = 5*Pi^2/12 + 160*log(2)/3 - 2945/72. (End)

Extensions

Incorrect formula deleted by R. J. Mathar, Feb 13 2016

A027769 a(n) = (n+1)*binomial(n+1, 9).

Original entry on oeis.org

9, 100, 605, 2640, 9295, 28028, 75075, 183040, 413270, 875160, 1755182, 3359200, 6172530, 10943240, 18795370, 31380096, 51074375, 81238300, 126544275, 193393200, 290435145, 429214500, 624962325, 897561600, 1272714300, 1783342704, 2471261100, 3389158080
Offset: 8

Views

Author

Thi Ngoc Dinh (via R. K. Guy)

Keywords

Comments

Number of 11-subsequences of [ 1, n ] with just 1 contiguous pair.
13208*a(n) is the number of permutations of (n+1) symbols that 9-commute with an (n+1)-cycle (see A233440 for definition), where 13208=A000757(9). - Luis Manuel Rivera Martínez, Feb 06 2014

Crossrefs

Programs

  • Mathematica
    Table[(n+1)*Binomial[n+1, 9], {n, 8, 35}] (* Amiram Eldar, Jan 30 2022 *)

Formula

G.f.: (9+x)*x^8/(1-x)^11.
From Amiram Eldar, Jan 30 2022: (Start)
Sum_{n>=8} 1/a(n) = 3*Pi^2/2 - 575499/39200.
Sum_{n>=8} (-1)^n/a(n) = 3*Pi^2/4 + 24576*log(2)/35 - 19365109/39200. (End)

A027770 a(n) = (n + 1)*binomial(n + 1, 10).

Original entry on oeis.org

10, 121, 792, 3718, 14014, 45045, 128128, 330616, 787644, 1755182, 3695120, 7407036, 14226212, 26313518, 47070144, 81719000, 138105110, 227779695, 367447080, 580870290, 901350450, 1374917115, 2064391680, 3054514320, 4458356760, 6425278860, 9150726816
Offset: 9

Views

Author

Thi Ngoc Dinh (via R. K. Guy)

Keywords

Comments

Number of 12-subsequences of [ 1, n ] with just one contiguous pair.
120288*a(n) is the number of permutations of (n+1) symbols that 10-commute with an (n+1)-cycle (see A233440 for definition), where 120288 = A000757(10). - Luis Manuel Rivera Martínez, Feb 07 2014

Crossrefs

Programs

  • Maple
    a:= n-> (n+1)*binomial(n+1, 10):
    seq(a(n), n=9..36);  # Alois P. Heinz, Oct 04 2019
  • Mathematica
    ((# + 1) Binomial[# + 1, 10] &) /@ Range[9, 48] (* Alonso del Arte, Oct 04 2019 *)

Formula

G.f.: (10 + x)*x^9/(1 - x)^12.
a(n) = C(n + 1, 10)*C(n + 1, 1). - Zerinvary Lajos, Jun 08 2005, corrected by R. J. Mathar, Feb 13 2016
From Amiram Eldar, Jan 30 2022: (Start)
Sum_{n>=9} 1/a(n) = 5257891/317520 - 5*Pi^2/3.
Sum_{n>=9} (-1)^(n+1)/a(n) = 5*Pi^2/6 + 84992*log(2)/63 - 299498341/317520. (End)

A027771 a(n) = (n+1)*binomial(n+1,11).

Original entry on oeis.org

11, 144, 1014, 5096, 20475, 69888, 210392, 572832, 1436058, 3359200, 7407036, 15519504, 31097794, 59907456, 111435000, 200880160, 352023165, 601277040, 1003321410, 1638819000, 2624841765, 4128783360, 6386711760, 9727323840, 14602906500, 21628990656
Offset: 10

Views

Author

Thi Ngoc Dinh (via R. K. Guy)

Keywords

Comments

Number of 13-subsequences of [ 1, n ] with just 1 contiguous pair.
1214673*a(n) is the number of permutations of (n+1) symbols that 11-commute with an (n+1)-cycle (see A233440 for definition), where 1214673 = A000757(11). - Luis Manuel Rivera Martínez, Feb 07 2014

Crossrefs

Programs

  • Mathematica
    Table[(n+1)*Binomial[n+1, 11], {n, 10, 35}] (* Amiram Eldar, Jan 30 2022 *)

Formula

G.f.: (11+x)*x^10/(1-x)^13.
From Amiram Eldar, Jan 30 2022: (Start)
Sum_{n>=10} 1/a(n) = 11*Pi^2/6 - 57138257/3175200.
Sum_{n>=10} (-1)^n/a(n) = 11*Pi^2/12 + 822272*log(2)/315 - 5773608863/3175200. (End)

A134515 Third column (k=2) of triangle A134832 (circular succession numbers).

Original entry on oeis.org

1, 0, 0, 10, 15, 168, 1008, 8244, 73125, 726440, 7939008, 94744494, 1225760627, 17088219120, 255365758560, 4072255216296, 69021889788969, 1239055874931312, 23484788783212480, 468656477004105810, 9821896865573503095
Offset: 0

Views

Author

Wolfdieter Lang, Jan 21 2008, Feb 22 2008

Keywords

Comments

a(n) enumerates circular permutations of {1,2,...,n+2} with exactly two successor pairs (i,i+1). Due to cyclicity also (n+2,1) is a successor pair.

Examples

			a(2)=0 because the 4!/4 = 6 circular permutations of n=4 elements (1,2,3,4), (1,4,3,2), (1,3,4,2),(1,2,4,3), (1,4,2,3) and (1,3,2,4) have 4,0,1,1,1 and 1 successor pair, respectively.
		

References

  • Ch. A. Charalambides, Enumerative Combinatorics, Chapman & Hall/CRC, Boca Raton, Florida, 2002, p. 183, eq. (5.15), for k=2.

Crossrefs

Cf. A135799 (column k=1).

Formula

E.g.f.: (d^2/dx^2) (x^2/2!)*(1-log(1-x))/e^x.
a(n) = (((n+2)*(n+1))/2)*A000757(n), n>=0.

A134833 Alternating row sums of triangle A134832.

Original entry on oeis.org

1, -1, 1, 0, -2, 12, -16, 144, 368, 4768, 39488, 412288, 4577280, 55671808, 731390976, 10335518720, 156303439872, 2518984822784, 43099089166336, 780268880543744, 14902336357040128, 299452809649520640, 6315501510334480384, 139485953831272710144, 3219718099932104622080
Offset: 0

Views

Author

Wolfdieter Lang, Jan 21 2008

Keywords

Crossrefs

Cf. A000142 (factorials as row sums of triangle A134832).

Programs

  • Mathematica
    A000757[n_] := (-1)^n + Sum[(-1)^k*n!/((n - k)*k!), {k, 0, n - 1}]; a[n_, n_] = 1; a[n_, 0] := A000757[n]; a[n_, k_] := a[n, k] = n/k*a[n - 1, k - 1]; Table[Sum[a[n, k]*(-1)^k, {k, 0, n}], {n, 0, 10}] (* G. C. Greubel, Nov 10 2016 *)

Formula

a(n) = Sum_{k=0..n} A134832(n,k)*(-1)^k for n>=0.

A135801 Fourth column (k=3) of triangle A134832 (circular succession numbers).

Original entry on oeis.org

1, 0, 0, 20, 35, 448, 3024, 27480, 268125, 2905760, 34402368, 442140972, 6128803135, 91137168640, 1447072631840, 24433531297776, 437138635330137, 8260372499542080, 164393521482487360, 3436814164696775940
Offset: 0

Views

Author

Wolfdieter Lang, Jan 21 2008, Feb 22 2008

Keywords

Comments

a(n) enumerates circular permutations of {1,2,...,n+3} with exactly three successor pairs (i,i+1). Due to cyclicity also (n+3,1) is a successor pair.

Examples

			a(1)=0 because the 4!/4 = 6 circular permutations of n=4 elements (1,2,3,4), (1,4,3,2), (1,3,4,2),(1,2,4,3), (1,4,2,3) and (1,3,2,4) have 4,0,1,1,1 and 1 successor pair, respectively.
		

References

  • Ch. A. Charalambides, Enumerative Combinatorics, Chapman & Hall/CRC, Boca Raton, Florida, 2002, p. 183, eq. (5.15), for k=3.

Crossrefs

Cf. A134515 (column k=2), A135802 (column k=4).

Programs

  • Mathematica
    f[n_] := (-1)^n + Sum[(-1)^k*n!/((n - k)*k!), {k, 0, n - 1}]; a[n_, n_] = 1; a[n_, 0] := f[n]; a[n_, k_] := a[n, k] = n/k*a[n - 1, k - 1]; Table[a[n, 3], {n, 3, 10}] (* G. C. Greubel, Nov 10 2016 *)

Formula

a(n) = binomial(n+3,3)*A000757(n), n>=0.
E.g.f.: (d^3/dx^3) (x^3/3!)*(1-log(1-x))/e^x.

A135807 Tenth column (k=9) of triangle A134832 (circular succession numbers).

Original entry on oeis.org

1, 0, 0, 220, 715, 16016, 180180, 2619760, 39503750, 642172960, 11111964864, 204016477080, 3959206825210, 80952590044480, 1739019535313720, 39150661649469744, 921633956154372175, 22640304292494917600
Offset: 0

Views

Author

Wolfdieter Lang, Jan 21 2008, Feb 22 2008

Keywords

Comments

a(n) enumerates circular permutations of {1,2,...,n+9} with exactly nine successor pairs (i,i+1). Due to cyclicity also (n+9,1) is a successor pair.

Examples

			a(0)=1 because from the 9!/9 = 40320 circular permutations of n=9 elements only one, namely (1,2,3,4,5,6,7,8,9), has nine successors.
		

References

  • Ch. A. Charalambides, Enumerative Combinatorics, Chapman & Hall/CRC, Boca Raton, Florida, 2002, p. 183, eq. (5.15), for k=9.

Crossrefs

Cf. A135806 (column k=8).

Programs

  • Mathematica
    f[n_] := (-1)^n + Sum[(-1)^k*n!/((n - k)*k!), {k, 0, n - 1}]; a[n_, n_] = 1; a[n_, 0] := f[n]; a[n_, k_] := a[n, k] = n/k*a[n - 1, k - 1]; Table[a[n, 9], {n, 9, 25}] (* G. C. Greubel, Nov 10 2016 *)
  • PARI
    a(n)=((-1)^n + sum( k=0, n-1, (-1)^k * binomial( n, k) * (n - k - 1)!))*binomial(n+9,9) \\ Charles R Greathouse IV, Nov 10 2016

Formula

a(n) = binomial(n+9,9)*A000757(n), n>=0.
E.g.f.: (d^9/dx^9) (x^9/9!)*(1-log(1-x))/e^x.
Previous Showing 11-20 of 24 results. Next