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.

Showing 1-6 of 6 results.

A092082 Triangle of numbers related to triangle A092083; generalization of Stirling numbers of second kind A008277, Lah-numbers A008297, ...

Original entry on oeis.org

1, 7, 1, 91, 21, 1, 1729, 511, 42, 1, 43225, 15015, 1645, 70, 1, 1339975, 523705, 69300, 4025, 105, 1, 49579075, 21240765, 3226405, 230300, 8330, 147, 1, 2131900225, 984172735, 166428990, 13820205, 621810, 15386, 196, 1, 104463111025
Offset: 1

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Author

Wolfdieter Lang, Mar 19 2004

Keywords

Comments

a(n,m) := S2(7; n,m) is the seventh triangle of numbers in the sequence S2(k;n,m), k=1..6: A008277 (unsigned Stirling 2nd kind), A008297 (unsigned Lah), A035342, A035469, A049029, A049385, respectively. a(n,1)=A008542(n), n>=1.
a(n,m) enumerates unordered n-vertex m-forests composed of m plane increasing 7-ary trees. Proof based on the a(n,m) recurrence. See also the F. Bergeron et al. reference, especially Table 1, first row and Example 1 for the e.g.f. for m=1. - Wolfdieter Lang, Sep 14 2007
Also the Bell transform of A008542(n+1). For the definition of the Bell transform see A264428. - Peter Luschny, Jan 26 2016

Examples

			{1}; {7,1}; {91,21,1}; {1729,511,42,1}; ...
		

Crossrefs

Cf. A092084 (row sums), A092085 (alternating row sums).

Programs

  • Maple
    # The function BellMatrix is defined in A264428.
    # Adds (1, 0, 0, 0, ..) as column 0.
    BellMatrix(n -> mul(6*k+1, k=0..n), 9); # Peter Luschny, Jan 26 2016
  • Mathematica
    mmax = 9; a[n_, m_] := n!*Coefficient[Series[((-1 + (1 - 6*x)^(-1/6))^m)/m!, {x, 0, mmax}], x^n];
    Flatten[Table[a[n, m], {n, 1, mmax}, {m, 1, n}]][[1 ;; 37]] (* Jean-François Alcover, Jun 22 2011, after e.g.f. *)
    rows = 9;
    t = Table[Product[6k+1, {k, 0, n}], {n, 0, rows}];
    T[n_, k_] := BellY[n, k, t];
    Table[T[n, k], {n, 1, rows}, {k, 1, n}] // Flatten (* Jean-François Alcover, Jun 22 2018, after Peter Luschny *)

Formula

a(n, m) = sum(|A051151(n, j)|*S2(j, m), j=m..n) (matrix product), with S2(j, m) := A008277(j, m) (Stirling2 triangle). Priv. comm. with Wolfdieter Lang by E. Neuwirth, Feb 15 2001; see also the 2001 Neuwirth reference. See the general comment on products of Jabotinsky matrices given under A035342.
a(n, m) = n!*A092083(n, m)/(m!*6^(n-m)); a(n+1, m) = (6*n+m)*a(n, m)+ a(n, m-1), n >= m >= 1; a(n, m) := 0, n
E.g.f. for m-th column: ((-1+(1-6*x)^(-1/6))^m)/m!.

A092086 Row sums of triangle A092083 (s2(7)).

Original entry on oeis.org

1, 22, 589, 17158, 523930, 16486744, 529725541, 17282788798, 570508962718, 19007589409636, 638032097840818, 21549790120416700, 731641432814800132, 24950167895840374876, 854088761155288136341, 29334095386695889771054
Offset: 1

Author

Wolfdieter Lang, Mar 19 2004

Keywords

Crossrefs

Cf. A092083.

Programs

  • Mathematica
    Rest[CoefficientList[Series[(-1+(1-36x)^(-1/6))/(7-(1-36x)^(-1/6)), {x,0,20}],x]] (* Harvey P. Dale, Jun 29 2011 *)

Formula

a(n) = Sum_{m=1..n} A092083(n, m), n>=1.
G.f.: (-1 + (1-36*x)^(-1/6))/(7-(1-36*x)^(-1/6)).

A092087 Alternating row sums of triangle A092083 (s2(7)).

Original entry on oeis.org

1, 20, 505, 14090, 415654, 12706406, 398165665, 12706132610, 411175121230, 13453601230544, 444162996339226, 14772945441872060, 494426375286105640, 16635957551869533770, 562327513989662942929, 19084061209362462745826
Offset: 0

Author

Wolfdieter Lang, Mar 19 2004

Keywords

Formula

a(n)= -sum(A092083(n, m)*(-1)^m, m=1..n), n>=1.
G.f.: (-1 +(1-36*x)^(-1/6))/(5+(1-36*x)^(-1/6)).

A132057 A convolution triangle of numbers obtained from A034904.

Original entry on oeis.org

1, 28, 1, 980, 56, 1, 37730, 2744, 84, 1, 1531838, 130340, 5292, 112, 1, 64337196, 6136956, 299782, 8624, 140, 1, 2766499428, 288408120, 16120314, 568008, 12740, 168, 1, 121034349975, 13561837212, 841627332, 34401528, 956970, 17640, 196, 1
Offset: 1

Author

Wolfdieter Lang Sep 14 2007

Keywords

Comments

a(n,1) = A034904(n). a(n,m)=: s2(8; n,m), a member of a sequence of unsigned triangles including s2(2; n,m)=A007318(n-1,m-1) (Pascal's triangle). s2(3;n,m)= A035324(n,m), s2(4; n,m)= A035529(n,m), s2(5; n,m)= A048882(n,m), s2(6; n,m)= A049375; s2(7; n,m)=A092083.

Examples

			{1}; {28,1}; {980,56,1}; (37730,2744,84,1);...
		

Crossrefs

Cf. A132058 (row sums), A132059 (negative of alternating row sums).

Programs

  • Mathematica
    a[n_, m_] := a[n, m] = 7*(7*(n-1) + m)*a[n-1, m]/n + m*a[n-1, m-1]/n;
    a[n_, m_] /; n < m = 0; a[_, 0] = 0; a[1, 1] = 1;
    Flatten[Table[a[n, m], {n, 1, 8}, {m, 1, n}]][[1 ;; 36]]
    (* Jean-François Alcover, Jun 17 2011 *)

Formula

a(n, m) = 7*(7*(n-1)+m)*a(n-1, m)/n + m*a(n-1, m-1)/n, n >= m >= 1; a(n, m) := 0, n
G.f. for m-th column: ((-1+(1-49*x)^(-1/7))/7)^m.

A132058 Row sums of triangle A132057 (s2(8)).

Original entry on oeis.org

1, 29, 1037, 40559, 1667583, 70782699, 3071608779, 135473190854, 6049729693582, 272822775416318, 12401578633961126, 567447248339504450, 26107796156861857866, 1206858263561650517658, 56014709781906608746434
Offset: 1

Author

Wolfdieter Lang Sep 14 2007

Keywords

Crossrefs

Cf. A092086 (row sums of s2(7)=A092083).

Formula

a(n)=sum(A132057(n, m), m=1..n), n>=1.
G.f.: (-1 + (1-49*x)^(-1/7))/(8-(1-49*x)^(-1/7)).

A132059 Alternating row sums of triangle A132057 (s2(8)).

Original entry on oeis.org

1, 27, 925, 35069, 1406679, 58491537, 2493656187, 108280678092, 4768395658314, 212335592489544, 9540877059969102, 431908789303835976, 19675192863275361294, 901089855844979674068, 41459199062515242868098
Offset: 1

Author

Wolfdieter Lang Sep 11 2007

Keywords

Crossrefs

Cf. A092087 (alternating row sums of s2(7)=A092083).

Formula

a(n)= -sum(A132057(n, m)*(-1)^m, m=1..n), n>=1.
G.f.: (-1 +(1-49*x)^(-1/7))/(6+(1-49*x)^(-1/7)).
Showing 1-6 of 6 results.