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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A231602 Triangular array read by rows: T(n,k) is the number of rooted labeled trees on n nodes that have exactly k nodes with outdegree = 1, n>=1, 0<=k<=n-1.

Original entry on oeis.org

1, 0, 2, 3, 0, 6, 4, 36, 0, 24, 65, 80, 360, 0, 120, 306, 1950, 1200, 3600, 0, 720, 4207, 12852, 40950, 16800, 37800, 0, 5040, 38424, 235592, 359856, 764400, 235200, 423360, 0, 40320, 573057, 2766528, 8481312, 8636544, 13759200, 3386880, 5080320, 0, 362880
Offset: 1

Views

Author

Geoffrey Critzer, Nov 11 2013

Keywords

Comments

T(n,k) is also the number of functions f:{1,2,...,n-1}->{1,2,...,n} that have exactly k elements whose preimage has cardinality = 1.
T(n,n-1) = n! = A000142(n).
Column k = 0 = A060356(n).
Row sums = n^(n-1) = A000169(n).
Refinement given by A248120. Sum coefficients of the partition polynomials with h_1 = (1') = t and all other h_n = (n') = 1 to obtain this entry. - Tom Copeland, Feb 01 2016

Examples

			1;
0, 2;
3, 0, 6;
4, 36, 0, 24;
65, 80, 360, 0, 120;
306, 1950, 1200, 3600, 0, 720;
4207, 12852, 40950, 16800, 37800, 0, 5040;
38424, 235592, 359856, 764400, 235200, 423360, 0, 40320;
....0..........0........
....|........./ \.......
....0........0...0......
.../ \.......|..........
..0   0......0..........
T(4,1) = 36.  Both of these graphs on 4 nodes have exactly 1 node that has outdegree = 1.  There are 12 + 24 = 36 labelings.
		

Crossrefs

Programs

  • Maple
    with(combinat): C:= binomial:
    b:= proc(t, i, u) option remember; `if`(t=0, 1,
          `if`(i<2, 0, b(t, i-1, u) +add(multinomial(t, t-i*j, i$j)
          *b(t-i*j, i-1, u-j)*u!/(u-j)!/j!, j=1..t/i)))
        end:
    T:= (n, k)-> C(n, k)*C(n-1, k)*k! *b(n-1-k$2, n-k):
    seq(seq(T(n, k), k=0..n-1), n=1..10);  # Alois P. Heinz, Nov 12 2013
  • Mathematica
    nn=8;Table[Table[Drop[Range[0,nn]!CoefficientList[Series[-ProductLog[x/(-1-x+x y)],{x,0,nn}],{x,y}],1][[r,c]],{c,1,r}],{r,1,nn}]//Grid

Formula

E.g.f. satisfies A(x,y) = y*x*A(x,y) + x*( exp(A(x,y)) - A(x,y) ).

A055313 Number of labeled rooted trees with n nodes and 12 leaves.

Original entry on oeis.org

13, 745290, 2153888100, 1850107896000, 813987254808000, 233983253596659840, 50146687652338368000, 8684014103185704192000, 1281139242561407305440000, 167044094432657294973120000
Offset: 13

Views

Author

Christian G. Bower, May 11 2000

Keywords

Crossrefs

Column 12 of A055302.

Programs

  • Magma
    [Factorial(n)*(n-12)^2*(n-11)^2*(n-10)*(n-9)*(n-8)*(n-7)*(n-6)*(n-5)*(n-4)*(n-3)*(n-2)*(n-1)*(9*n^8 - 708*n^7 + 24018*n^6 - 458136*n^5 + 5363513*n^4 - 39369364*n^3 + 176423596*n^2 - 439700816*n + 464486400) / 352423730384732160000: n in [13..25]]; // Vincenzo Librandi, Jul 25 2014
  • Mathematica
    Table[n! * (n-12)^2*(n-11)^2*(n-10)*(n-9)*(n-8)*(n-7)*(n-6)*(n-5)*(n-4)*(n-3)*(n-2)*(n-1)*(9*n^8 - 708*n^7 + 24018*n^6 - 458136*n^5 + 5363513*n^4 - 39369364*n^3 + 176423596*n^2 - 439700816*n + 464486400) / 352423730384732160000,{n,13,25}] (* Vaclav Kotesovec, Jul 25 2014 *)

Formula

a(n) = n! * (n-12)^2*(n-11)^2*(n-10)*(n-9)*(n-8)*(n-7)*(n-6)*(n-5)*(n-4)*(n-3)*(n-2)*(n-1)*(9*n^8 - 708*n^7 + 24018*n^6 - 458136*n^5 + 5363513*n^4 - 39369364*n^3 + 176423596*n^2 - 439700816*n + 464486400) / 352423730384732160000. - Vaclav Kotesovec, Jul 25 2014

A055304 Number of labeled rooted trees with n nodes and 3 leaves.

Original entry on oeis.org

4, 140, 3000, 54600, 940800, 16087680, 279417600, 4989600000, 92207808000, 1769511744000, 35321737651200, 733823266176000, 15866448998400000, 356873052856320000, 8344427063132160000, 202660737281114112000
Offset: 4

Views

Author

Christian G. Bower, May 11 2000

Keywords

Crossrefs

Column 3 of A055302.

Programs

  • Magma
    [Factorial(n)*(n-3)*(n-2)*(n-1)*(3*n-8)/144 : n in [4..25]]; // Vincenzo Librandi, Jul 25 2014
  • Maple
    seq(n!*(n-3)*(n-2)*(n-1)*(3*n-8)/144, n=4..100); # Robert Israel, Jul 25 2014
  • Mathematica
    Table[n! * (n-3)*(n-2)*(n-1)*(3*n-8)/144,{n,4,20}] (* Vaclav Kotesovec, Jul 25 2014 *)

Formula

a(n) = (n!/3!)*Stirling2(n-1, n-3). - Vladeta Jovovic, Jan 28 2004
a(n) = n! * (n-3)*(n-2)*(n-1)*(3*n-8)/144. - Vaclav Kotesovec, Jul 25 2014
E.g.f.: x^4*(2*x+1)/(6*(1-x)^5). - Robert Israel, Jul 25 2014

A055305 Number of labeled rooted trees with n nodes and 4 leaves.

Original entry on oeis.org

5, 450, 18900, 588000, 15876000, 400075200, 9779616000, 237105792000, 5779453680000, 142845262560000, 3599700616512000, 92818726640640000, 2454539660052480000, 66664716210892800000, 1861170036255129600000
Offset: 5

Views

Author

Christian G. Bower, May 11 2000

Keywords

Crossrefs

Column 4 of A055302.

Programs

  • Magma
    [Factorial(n)*(n-4)^2*(n-3)^2*(n-2)*(n-1)/1152 : n in [5..25]]; // Vincenzo Librandi, Jul 25 2014
  • Mathematica
    Table[n! * (n-4)^2*(n-3)^2*(n-2)*(n-1)/1152,{n,5,20}] (* Vaclav Kotesovec, Jul 25 2014 *)

Formula

a(n) = n! * (n-4)^2*(n-3)^2*(n-2)*(n-1)/1152. - Vaclav Kotesovec, Jul 25 2014

A055306 Number of labeled rooted trees with n nodes and 5 leaves.

Original entry on oeis.org

6, 1302, 101136, 5143824, 210198240, 7593173280, 255415628160, 8252203639680, 261173083691520, 8202954132172800, 257956727815987200, 8172268419809894400, 261973287647034163200, 8524055367713146060800
Offset: 6

Views

Author

Christian G. Bower, May 11 2000

Keywords

Crossrefs

Column 5 of A055302.

Programs

  • Magma
    [Factorial(n)*(n-5)*(n-4)*(n-3)*(n-2)*(n-1)*(15*n^3 - 195*n^2 + 830*n - 1152)/691200 : n in [6..25]]; // Vincenzo Librandi, Jul 25 2014
  • Mathematica
    Table[n! * (n-5)*(n-4)*(n-3)*(n-2)*(n-1)*(15*n^3 - 195*n^2 + 830*n - 1152)/691200,{n,6,20}] (* Vaclav Kotesovec, Jul 25 2014 *)

Formula

a(n) = n! * (n-5)*(n-4)*(n-3)*(n-2)*(n-1)*(15*n^3 - 195*n^2 + 830*n - 1152)/691200. - Vaclav Kotesovec, Jul 25 2014
E.g.f: x^6*(1+22*x+58*x^2+24*x^3)/(120*(1-x)^9). - Robert Israel, Jul 25 2014

A055307 Number of labeled rooted trees with n nodes and 6 leaves.

Original entry on oeis.org

7, 3528, 486864, 39160800, 2357586000, 119409111360, 5426122141440, 230006844587520, 9326497051872000, 367969396354560000, 14295131088292454400, 551514022702420377600, 21263333439482226892800
Offset: 7

Views

Author

Christian G. Bower, May 11 2000

Keywords

Crossrefs

Column 6 of A055302.

Programs

  • Magma
    [Factorial(n)*(n-6)^2*(n-5)^2*(n-4)*(n-3)*(n-2)*(n-1)*(3*n^2-29*n+ 64)/8294400: n in [7..25]]; // Vincenzo Librandi, Jul 25 2014
  • Maple
    seq(n! * (n-6)^2*(n-5)^2*(n-4)*(n-3)*(n-2)*(n-1)*(3*n^2 - 29*n + 64)/8294400, n=7..100); # Robert Israel, Jul 25 2014
  • Mathematica
    Table[n! * (n-6)^2*(n-5)^2*(n-4)*(n-3)*(n-2)*(n-1)*(3*n^2 - 29*n + 64)/8294400,{n,7,20}] (* Vaclav Kotesovec, Jul 25 2014 *)

Formula

a(n) = n! * (n-6)^2*(n-5)^2*(n-4)*(n-3)*(n-2)*(n-1)*(3*n^2 - 29*n + 64)/8294400. - Vaclav Kotesovec, Jul 25 2014
E.g.f: x^7*(120*x^4+444*x^3+328*x^2+52*x+1)/(720*(1-x)^11). - Robert Israel, Jul 25 2014

A055308 Number of labeled rooted trees with n nodes and 7 leaves.

Original entry on oeis.org

8, 9144, 2178000, 270111600, 23449219200, 1635398519040, 98861289246720, 5425893817344000, 278673669001728000, 13673851998782976000, 650477329618365849600, 30322668859342072012800
Offset: 8

Views

Author

Christian G. Bower, May 11 2000

Keywords

Crossrefs

Column 7 of A055302.

Programs

  • Magma
    [Factorial(n)*(n-7)*(n-6)*(n-5)*(n-4)*(n-3)*(n-2)*(n-1)*(63*n^5- 1890*n^4+22365*n^3-130186*n^2+371672*n-414720)/14631321600: n in [8..25]]; // Vincenzo Librandi, Jul 25 2014
  • Mathematica
    Table[n! * (n-7)*(n-6)*(n-5)*(n-4)*(n-3)*(n-2)*(n-1)*(63*n^5 - 1890*n^4 + 22365*n^3 - 130186*n^2 + 371672*n - 414720)/14631321600,{n,8,20}] (* Vaclav Kotesovec, Jul 25 2014 *)

Formula

a(n) = n! * (n-7)*(n-6)*(n-5)*(n-4)*(n-3)*(n-2)*(n-1)*(63*n^5 - 1890*n^4 + 22365*n^3 - 130186*n^2 + 371672*n - 414720)/14631321600. - Vaclav Kotesovec, Jul 25 2014

A055309 Number of labeled rooted trees with n nodes and 8 leaves.

Original entry on oeis.org

9, 22950, 9236700, 1731510000, 213034536000, 20154167953920, 1599866940672000, 112412172128256000, 7240640845838400000, 437993205197708160000, 25315591135036262860800
Offset: 9

Views

Author

Christian G. Bower, May 11 2000

Keywords

Crossrefs

Column 8 of A055302.

Programs

  • Magma
    [Factorial(n)*(n-8)^2*(n-7)^2*(n-6)*(n-5)*(n-4)*(n-3)*(n-2)*(n-1)*(9*n^4 - 234*n^3 + 2211*n^2 - 8938*n + 12960)/234101145600 : n in [9..25]]; // Vincenzo Librandi, Jul 25 2014
  • Mathematica
    Table[n! * (n-8)^2*(n-7)^2*(n-6)*(n-5)*(n-4)*(n-3)*(n-2)*(n-1)*(9*n^4 - 234*n^3 + 2211*n^2 - 8938*n + 12960)/234101145600,{n,9,20}] (* Vaclav Kotesovec, Jul 25 2014 *)

Formula

a(n) = n! * (n-8)^2*(n-7)^2*(n-6)*(n-5)*(n-4)*(n-3)*(n-2)*(n-1)*(9*n^4 - 234*n^3 + 2211*n^2 - 8938*n + 12960)/234101145600. - Vaclav Kotesovec, Jul 25 2014

A055310 Number of labeled rooted trees with n nodes and 9 leaves.

Original entry on oeis.org

10, 56210, 37621320, 10493357160, 1803842280240, 228599313742800, 23567044281580800, 2099312576058297600, 168119161594140556800, 12440787291129176179200, 867641306901247726848000
Offset: 10

Views

Author

Christian G. Bower, May 11 2000

Keywords

Crossrefs

Column 9 of A055302.

Programs

  • Magma
    [Factorial(n)*(n-9)*(n-8)*(n-7)*(n-6)*(n-5)*(n-4)*(n-3)*(n-2)*(n-1)*(135*n^7 - 7245*n^6 + 164745*n^5 - 2054535*n^4 + 15148840*n^3 - 65892420*n^2 + 156108464*n - 154828800)/505658474496000: n in [10..25]]; // Vincenzo Librandi, Jul 25 2014
  • Mathematica
    Table[n! * (n-9)*(n-8)*(n-7)*(n-6)*(n-5)*(n-4)*(n-3)*(n-2)*(n-1)*(135*n^7 - 7245*n^6 + 164745*n^5 - 2054535*n^4 + 15148840*n^3 - 65892420*n^2 + 156108464*n - 154828800)/505658474496000,{n,10,20}] (* Vaclav Kotesovec, Jul 25 2014 *)

Formula

a(n) = n! * (n-9)*(n-8)*(n-7)*(n-6)*(n-5)*(n-4)*(n-3)*(n-2)*(n-1)*(135*n^7 - 7245*n^6 + 164745*n^5 - 2054535*n^4 + 15148840*n^3 - 65892420*n^2 + 156108464*n - 154828800)/505658474496000. - Vaclav Kotesovec, Jul 25 2014

A055311 Number of labeled rooted trees with n nodes and 10 leaves.

Original entry on oeis.org

11, 135036, 148478616, 60841500720, 14441439612600, 2425616445732480, 321683306528263680, 36020400612748231680, 3559225274902019923200, 320000251320623922048000, 26762519467151924853196800
Offset: 11

Views

Author

Christian G. Bower, May 11 2000

Keywords

Crossrefs

Column 10 of A055302.

Programs

  • Magma
    [Factorial(n)*(n-10)^2*(n-9)^2*(n-8)*(n-7)*(n-6)*(n-5)*(n-4)*(n-3)*(n-2)*(n-1)*(15*n^6 - 735*n^5 + 14715*n^4 - 153617*n^3 + 878862*n^2 - 2601592*n + 3096576) / 10113169489920000: n in [11..25]]; // Vincenzo Librandi, Jul 25 2014
  • Mathematica
    Table[n! * (n-10)^2*(n-9)^2*(n-8)*(n-7)*(n-6)*(n-5)*(n-4)*(n-3)*(n-2)*(n-1)*(15*n^6 - 735*n^5 + 14715*n^4 - 153617*n^3 + 878862*n^2 - 2601592*n + 3096576)/10113169489920000,{n,11,20}] (* Vaclav Kotesovec, Jul 25 2014 *)

Formula

a(n) = n! * (n-10)^2*(n-9)^2*(n-8)*(n-7)*(n-6)*(n-5)*(n-4)*(n-3)*(n-2)*(n-1)*(15*n^6 - 735*n^5 + 14715*n^4 - 153617*n^3 + 878862*n^2 - 2601592*n + 3096576)/10113169489920000. - Vaclav Kotesovec, Jul 25 2014
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