A098623
Consider the family of directed multigraphs enriched by the species of set partitions. Sequence gives number of those multigraphs with n labeled arcs.
Original entry on oeis.org
1, 1, 8, 109, 2229, 62684, 2289151, 104344153, 5767234550, 378073098155, 28888082263581, 2536660090249102, 253007765488793325, 28383529110762969901, 3551558435250676339536, 492092920443604792460905, 75025155137863150912784409, 12516480979952118669729618300
Offset: 0
- G. Paquin, Dénombrement de multigraphes enrichis, Mémoire, Math. Dept., Univ. Québec à Montréal, 2004.
- Andrew Howroyd, Table of n, a(n) for n = 0..200
- G. Labelle, Counting enriched multigraphs according to the number of their edges (or arcs), Discrete Math., 217 (2000), 237-248.
- G. Paquin, Dénombrement de multigraphes enrichis, Mémoire, Math. Dept., Univ. Québec à Montréal, 2004. [Cached copy, with permission]
-
\\ here R(n) is A000110 as e.g.f.
egfA020556(n)={my(bell=serlaplace(exp(exp(x + O(x^(2*n+1)))-1))); sum(i=0, n, sum(k=0, i, (-1)^k*binomial(i, k)*polcoef(bell, 2*i-k))*x^i/i!) + O(x*x^n)}
EnrichedGdSeq(R)={my(n=serprec(R, x)-1, B=subst(egfA020556(n), x, log(1+x + O(x*x^n)))); Vec(serlaplace(subst(B, x, R-polcoef(R,0))))}
R(n)={exp(exp(x + O(x*x^n))-1)}
EnrichedGdSeq(R(20)) \\ Andrew Howroyd, Jan 12 2021
A014505
Number of digraphs with unlabeled (non-isolated) nodes and n labeled edges.
Original entry on oeis.org
1, 1, 6, 68, 1206, 29982, 981476, 40515568, 2044492988, 123175320988, 8697475219688, 709097832452880, 65934837808883016, 6920436929999656936, 812724019581549433520, 105986960037601701495680
Offset: 0
- G. Paquin, Dénombrement de multigraphes enrichis, Mémoire, Math. Dept., Univ. Québec à Montréal, 2004.
- G. Labelle, Counting enriched multigraphs according to the number of their edges (or arcs), Discrete Math., 217 (2000), 237-248.
- G. Paquin, Dénombrement de multigraphes enrichis, Mémoire, Math. Dept., Univ. Québec à Montréal, 2004. [Cached copy, with permission]
A047865
Number of derangements of n where minimal cycle size is at least 4.
Original entry on oeis.org
1, 0, 0, 0, 6, 24, 120, 720, 6300, 58464, 586656, 6384960, 76471560, 994831200, 13939507296, 209097854784, 3345235180560, 56866395720960, 1023601917024000, 19448577603454464, 388972171805410656, 8168409582839579520, 179704944537482689920
Offset: 0
- H. S. Wilf, Generatingfunctionology, Academic Press, NY, 1990, p. 147, Eq. 5.2.9 (q=3).
-
with(combstruct): ZL3:=[S,{S=Set(Cycle(Z,card>3))},labeled]:
seq (count (ZL3, size=n), n=0..21); # Zerinvary Lajos, Sep 26 2007
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nn=20;Range[0,nn]!CoefficientList[Series[Exp[-x-x^2/2-x^3/3]/(1-x),{x,0,nn}],x] (* Geoffrey Critzer, Nov 11 2012 *)
A274760
The multinomial transform of A001818(n) = ((2*n-1)!!)^2.
Original entry on oeis.org
1, 1, 10, 478, 68248, 21809656, 13107532816, 13244650672240, 20818058883902848, 48069880140604832128, 156044927762422185270016, 687740710497308621254625536, 4000181720339888446834235653120, 29991260979682976913756629498334208
Offset: 0
Some a(n) formulas, see A036039:
a(0) = 1
a(1) = 1*x(1)
a(2) = 1*x(2) + 1*x(1)^2
a(3) = 2*x(3) + 3*x(1)*x(2) + 1*x(1)^3
a(4) = 6*x(4) + 8*x(1)*x(3) + 3*x(2)^2 + 6*x(1)^2*x(2) + 1*x(1)^4
a(5) = 24*x(5) + 30*x(1)*x(4) + 20*x(2)*x(3) + 20*x(1)^2*x(3) + 15*x(1)*x(2)^2 + 10*x(1)^3*x(2) + 1*x(1)^5
- N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 1995, pp. 18-23.
- M. Bernstein and N. J. A. Sloane, Some Canonical Sequences of Integers, arXiv:math/0205301 [math.CO], 2002; Linear Algebra and its Applications, Vol. 226-228 (1995), pp. 57-72. Erratum 320 (2000), 210. [Link to arXiv version]
- M. Bernstein and N. J. A. Sloane, Some canonical sequences of integers, Linear Alg. Applications, 226-228 (1995), 57-72; erratum 320 (2000), 210. [Link to Lin. Alg. Applic. version together with omitted figures]
- N. J. A. Sloane, Transforms.
- Eric W. Weisstein MathWorld, Exponential Transform.
-
nmax:= 13: b := proc(n): (doublefactorial(2*n-1))^2 end: a:= proc(n) option remember: if n=0 then 1 else add(((n-1)!/(n-k)!) * b(k) * a(n-k), k=1..n) fi: end: seq(a(n), n = 0..nmax); # End first MNL program.
nmax:=13: b := proc(n): (doublefactorial(2*n-1))^2 end: t1 := exp(add(b(n)*x^n/n, n = 1..nmax+1)): t2 := series(t1, x, nmax+1): a := proc(n): n!*coeff(t2, x, n) end: seq(a(n), n = 0..nmax); # End second MNL program.
nmax:=13: b := proc(n): (doublefactorial(2*n-1))^2 end: f := series(log(1+add(s(n)*x^n/n!, n=1..nmax)), x, nmax+1): d := proc(n): n*coeff(f, x, n) end: a(0) := 1: a(1) := b(1): s(1) := b(1): for n from 2 to nmax do s(n) := solve(d(n)-b(n), s(n)): a(n):=s(n): od: seq(a(n), n=0..nmax); # End third MNL program.
-
b[n_] := (2*n - 1)!!^2;
a[0] = 1; a[n_] := a[n] = Sum[((n-1)!/(n-k)!)*b[k]*a[n-k], {k, 1, n}];
Table[a[n], {n, 0, 13}] (* Jean-François Alcover, Nov 17 2017 *)
A014501
Number of graphs with loops, having unlabeled (non-isolated) nodes and n labeled edges.
Original entry on oeis.org
1, 2, 7, 43, 403, 5245, 89132, 1898630, 49209846, 1517275859, 54669946851, 2269075206395, 107199678164289, 5707320919486026, 339510756324234931, 22400182888853554291, 1628654713107465602783, 129754625253841669625051
Offset: 0
- G. Paquin, Dénombrement de multigraphes enrichis, Mémoire, Math. Dept., Univ. Québec à Montréal, 2004.
- Andrew Howroyd, Table of n, a(n) for n = 0..200
- G. Labelle, Counting enriched multigraphs according to the number of their edges (or arcs), Discrete Math., 217 (2000), 237-248.
- G. Paquin, Dénombrement de multigraphes enrichis, Mémoire, Math. Dept., Univ. Québec à Montréal, 2004. [Cached copy, with permission]
A355284
Expansion of e.g.f. 1 / (1 + x + x^2/2 + log(1 - x)).
Original entry on oeis.org
1, 0, 0, 2, 6, 24, 200, 1560, 12936, 130368, 1458432, 17623440, 233922480, 3376625472, 52382131776, 870882440064, 15459372915840, 291596692838400, 5824039155720192, 122814724467223296, 2726547887891407104, 63562453551393223680, 1552499303360183700480
Offset: 0
-
nmax = 22; CoefficientList[Series[1/(1 + x + x^2/2 + Log[1 - x]), {x, 0, nmax}], x] Range[0, nmax]!
a[0] = 1; a[n_] := a[n] = Sum[Binomial[n, k] (k - 1)! a[n - k], {k, 3, n}]; Table[a[n], {n, 0, 22}]
-
my(x='x+O('x^30)); Vec(serlaplace(1/(1 + x + x^2/2 + log(1 - x)))) \\ Michel Marcus, Jun 27 2022
A098233
Consider the family of ordinary multigraphs. Sequence gives the triangle read by rows giving coefficients of polynomials arising from enumeration of those multigraphs on n edges.
Original entry on oeis.org
1, 1, 1, 1, 1, 1, 4, 7, 3, 1, 1, 13, 46, 47, 25, 6, 1, 1, 40, 295, 587, 516, 235, 65, 10, 1, 1, 121, 1846, 6715, 9690, 7053, 3006, 800, 140, 15, 1, 1, 364, 11347, 73003, 170051, 189458, 119211, 46795, 12201, 2170, 266, 21, 1, 1, 1093, 68986, 768747
Offset: 0
The first few polynomials are:
1,
x^2,
x^2+x^3+x^4,
x^2+4x^3+7x^4+3x^5+x^6,
x^2+13x^3+46x^4+47x^5+25x^6+6x^7+x^8,
x^2+40x^3+295x^4+587x^5+516x^6+235x^7+65x^8+10x^9+x^10,
...
Triangle starts:
1;
1;
1, 1, 1;
1, 4, 7, 3, 1;
1, 13, 46, 47, 25, 6, 1;
1, 40, 295, 587, 516, 235, 65, 10, 1;
...
- G. Paquin, Dénombrement de multigraphes enrichis, Mémoire, Math. Dept., Univ. Québec à Montréal, 2004.
- Steve Butler, Fan Chung, Jay Cummings, and R. L. Graham, Juggling card sequences, arXiv:1504.01426 [math.CO], 2015.
- L. Comtet, Birecouvrements et birevêtements d'un ensemble fini, Studia Sci. Math. Hungar 3 (1968): 137-152. [Annotated scanned copy. Warning: the table of v(n,k) has errors.]
- G. Paquin, Dénombrement de multigraphes enrichis, Mémoire, Math. Dept., Univ. Québec à Montréal, 2004. [Cached copy, with permission]
A098362
Consider the family of multigraphs enriched by the species of partitions. Sequence gives the triangle read by rows giving coefficients of polynomials arising from enumeration of those multigraphs on n arcs of 7 different colors.
Original entry on oeis.org
1, 7, 105, 196, 49, 1673, 11564, 13181, 4116, 343, 28133, 566636, 1643999, 1407672, 453446, 57624, 2401, 496769, 26784380, 168588665, 298710468, 207080419, 65115120, 9772070, 672280, 16807
Offset: 0
1, 7x^2, 105x^2+196x^3+49x^4, 1673x^2+11564x^3+13181x^4+4116x^5+343x^6, 28133x^2+566636x^3+1643999x^4+1407672x^5+453446x^6+57624x^7+2401x^8, ...
- G. Paquin, Dénombrement de multigraphes enrichis, Mémoire, Math. Dept., Univ. Québec à Montréal, 2004.
A098621
Consider the family of multigraphs enriched by the species of partitions. Sequence gives number of those multigraphs with n loops and edges.
Original entry on oeis.org
1, 2, 11, 95, 1173, 19364, 407447, 10552664, 327719713, 119600021230, 504784756672, 24321086122048
Offset: 0
- G. Paquin, Dénombrement de multigraphes enrichis, Mémoire, Math. Dept., Univ. Québec à Montréal, 2004.
A098624
Consider the family of multigraphs enriched by the species of derangements. Sequence gives number of those multigraphs with n labeled edges.
Original entry on oeis.org
1, 0, 1, 2, 15, 84, 750, 6852, 79639, 1006184, 14875218, 241078100, 4392257716, 87279581232, 1905609327583, 45008114794874, 1150897256534370, 31580332783936416, 928535967078634497, 29090873853321687666, 969132936087009709174, 34198721664081728281400
Offset: 0
- G. Paquin, Dénombrement de multigraphes enrichis, Mémoire, Math. Dept., Univ. Québec à Montréal, 2004.
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