A002501
a(n) = 7^n - 3*4^n + 2*3^n.
Original entry on oeis.org
1, 19, 205, 1795, 14221, 106819, 778765, 5581315, 39606541, 279447619, 1965098125, 13792018435, 96690872461, 677427332419, 4744368982285, 33220131761155, 232579232659981, 1628208214321219, 11398072876175245, 79788974736297475, 558532690864457101
Offset: 1
- N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
- N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
Better definition and more terms from Goran Kilibarda,
Vladeta Jovovic, Apr 14 2004
A002502
Number of connected relations.
Original entry on oeis.org
1, 65, 1795, 36317, 636331, 10365005, 162470155, 2495037197, 37898120011, 572284920845, 8614868501515, 129467758660877, 1943971108806091, 29175170378428685, 437752102106036875, 6567275797761209357
Offset: 1
- N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
- N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
-
LinearRecurrence[{38,-539,3622,-11640,14400},{1,65,1795,36317,636331},20] (* Harvey P. Dale, Mar 24 2017 *)
A093733
Number of connected relations.
Original entry on oeis.org
1, 665, 106819, 10365005, 805351531, 56294206205, 3735873535339, 241600284318365, 15423235216318411, 978180744322139645, 61834480769377286059, 3902270609960140639325, 246057483524862034206091, 15508484277325946034039485, 977254123876968508188975979
Offset: 1
- T. D. Noe, Table of n, a(n) for n = 1..100
- Goran Kilibarda and Vladeta Jovovic, Enumeration of some classes of T_0-hypergraphs, arXiv:1411.4187 [math.CO], 2014.
- G. Kreweras, Inversion des polynômes de Bell bidimensionnels et application au dénombrement des relations binaires connexes, C. R. Acad. Sci. Paris Ser. A-B 268 1969 A577-A579.
- Index entries for linear recurrences with constant coefficients, signature (-195, 15886, -726290, 20952193, -403792115, 5336718048, -48588590600, 299693200656, -1195947048240, 2785165036416, -2872859996160).
-
Table[63^n-6*32^n-15*18^n+30*17^n-10*14^n+120*11^n-120*10^n+30*9^n-270*8^n+360*7^n-120*6^n, {n,1,25}] (* G. C. Greubel, Oct 06 2017 *)
CoefficientList[Series[x (96368590080x^9+27682953984x^8-13185435000x^7+774468980x^6+ 143028190x^5-19071533x^4+626800x^3+6970x^2-470x-1)/((6x-1)(7x-1)(8x-1)(9x-1)(10x-1)(11x-1)(14x-1)(17x-1)(18x-1)(32x-1)(63x-1)),{x,0,20}],x] (* or *) LinearRecurrence[{195,-15886,726290,-20952193,403792115,-5336718048,48588590600,-299693200656,1195947048240,-2785165036416,2872859996160},{0,1,665,106819,10365005,805351531,56294206205,3735873535339,241600284318365,15423235216318411,978180744322139645},20] (* Harvey P. Dale, Sep 23 2023 *)
-
for(n=1,25, print1(63^n-6*32^n-15*18^n+30*17^n-10*14^n+120*11^n-120*10^n+30*9^n-270*8^n+360*7^n-120*6^n, ", ")) \\ G. C. Greubel, Oct 06 2017
A114936
Number of connected (4,n)-hypergraphs (without empty edges).
Original entry on oeis.org
0, 1, 10, 135, 1992, 30166, 458885, 6965225, 105358102, 1588998756, 23915093535, 359444209015, 5397938190512, 81022969645346, 1215801458118985, 18240857019892005, 273644796626023722, 4104936328561231936
Offset: 0
-
With[{nmax = 50}, CoefficientList[Series[(1/4!)*(Exp[15*x] - 4*Exp[8*x] + 6*Exp[7*x] - 3*Exp[6*x] + 12*Exp[5*x] - 24*Exp[4*x] + 23*Exp[3*x] - 11*Exp[2*x] + 6*Exp[x] - 6), {x, 0, nmax}], x] Range[0, nmax]!] (* G. C. Greubel, Oct 07 2017 *)
-
x='x+O('x^50); concat([0], Vec(serlaplace((1/4!)*(exp(15*x) - 4*exp(8*x) + 6*exp(7*x) - 3*exp(6*x) + 12*exp(5*x) - 24*exp(4*x) + 23*exp(3*x) - 11*exp(2*x) + 6*exp(x) - 6)))) \\ G. C. Greubel, Oct 07 2017
A114935
Number of connected (3,n)-hypergraphs (without empty edges).
Original entry on oeis.org
0, 1, 6, 44, 332, 2476, 18136, 130824, 933372, 6610676, 46603616, 327603904, 2298933412, 16115938476, 112906938696, 790735321784, 5536710117452, 38763269947876, 271368229299376, 1899679393564464, 13298164198917492
Offset: 0
-
With[{nmax = 50}, CoefficientList[Series[(1/3!)*(Exp[7*x] - 3*Exp[4*x] + 5*Exp[3*x] - 3*Exp[2*x] + 2*Exp[x] - 2), {x, 0, nmax}], x] Range[0, nmax]!] (* G. C. Greubel, Oct 07 2017 *)
-
x='x+O('x^50); concat([0], Vec(serlaplace((1/3!)*(exp(7*x) -3*exp(4*x) +5*exp(3*x) -3*exp(2*x) +2*exp(x) - 2)))) \\ G. C. Greubel, Oct 07 2017
A114937
Number of connected (5,n)-hypergraphs (without empty edges).
Original entry on oeis.org
0, 1, 15, 336, 8880, 254596, 7606446, 231899522, 7137539256, 220623286632, 6831984816402, 211719998195278, 6562887569336652, 203453536535818388, 6307290799931347878, 195532244201392935354, 6061637498660735815968
Offset: 0
A114934
Number of connected (5,n)-hypergraphs (without empty edges and without multiple edges).
Original entry on oeis.org
0, 0, 0, 21, 2773, 148365, 5878391, 204819447, 6721694469, 214306917321, 6736603947907, 210284186632443, 6541309609120385, 203129541349695597, 6302428271530970943, 195459285517696665759, 6060542952694406463421
Offset: 0
-
With[{nmax = 50}, CoefficientList[Series[(1/5!)*(Exp[31*x] - 5*Exp[16*x] - 10*Exp[15*x] - 10*Exp[10*x] + 20*Exp[9*x] + 40*Exp[8*x] + 65*Exp[7*x] - 30*Exp[6*x] - 96*Exp[5*x] - 45*Exp[4*x] + 20*Exp[3*x] + 50*Exp[2*x] + 24*Exp[x] - 24), {x, 0, nmax}], x] Range[0, nmax]!] (* G. C. Greubel, Oct 07 2017 *)
-
x='x+O('x^50); concat([0,0,0], Vec(serlaplace((1/5!)*(exp(31*x) - 5*exp(16*x) - 10*exp(15*x) - 10*exp(10*x) + 20*exp(9*x) + 40*exp(8*x) + 65*exp(7*x) - 30*exp(6*x) - 96*exp(5*x) - 45*exp(4*x) + 20*exp(3*x) + 50*exp(2*x) + 24*exp(x) - 24)))) \\ G. C. Greubel, Oct 07 2017
A114933
Number of connected (4,n)-hypergraphs (without empty edges and without multiple edges).
Original entry on oeis.org
0, 0, 0, 32, 1094, 23055, 405475, 6575842, 102567444, 1569195485, 23775369725, 358461659952, 5391042181294, 80974624209115, 1215462744452775, 18238484835400862, 273628186560143144, 4104820038944901945
Offset: 0
-
With[{nmax = 50}, CoefficientList[Series[(1/4!)*(Exp[15*x] - 4*Exp[8*x] - 6*Exp[7*x] - 3*Exp[6*x] + 12*Exp[5*x] + 12*Exp[4*x] - Exp[3*x] - 11*Exp[2*x] - 6*Exp[x] + 6), {x, 0, nmax}], x] Range[0, nmax]!] (* G. C. Greubel, Oct 07 2017 *)
-
x='x+O('x^50); concat([0,0,0], Vec(serlaplace((1/4!)*(exp(15*x)-4*exp(8*x)-6*exp(7*x)-3*exp(6*x)+12*exp(5*x)+12*exp(4*x)-exp(3*x)-11*exp(2*x)-6*exp(x)+6)))) \\ G. C. Greubel, Oct 07 2017
A226658
T(n,k)=Number of nXk 0..4 arrays of sums of 2X2 subblocks of some (n+1)X(k+1) binary array.
Original entry on oeis.org
5, 19, 19, 65, 205, 65, 211, 1795, 1795, 211, 665, 14221, 36317, 14221, 665, 2059, 106819, 636331, 636331, 106819, 2059, 6305, 778765, 10365005, 23679901, 10365005, 778765, 6305, 19171, 5581315, 162470155, 805351531, 805351531, 162470155
Offset: 1
Some solutions for n=3 k=4
..1..1..1..0....0..1..1..1....0..1..1..0....1..0..1..1....1..0..2..3
..3..1..1..2....1..1..2..1....1..2..2..2....1..2..3..2....1..2..2..1
..3..2..2..3....3..1..2..3....2..1..2..3....2..3..2..1....3..3..1..0
A114932
Number of connected (3,n)-hypergraphs (without empty edges and without multiple edges).
Original entry on oeis.org
0, 0, 1, 25, 267, 2265, 17471, 128765, 927067, 6591505, 46545591, 327428805, 2298406067, 16114352345, 112902172111, 790721005645, 5536667136267, 38763140938785, 271367842141031, 1899678231827285, 13298160713181667
Offset: 0
-
With[{nmax = 50}, CoefficientList[Series[(1/3!)*(Exp[7*x] - 3*Exp[4*x] - Exp[3*x] + 3*Exp[2*x] + 2*Exp[x] - 2), {x, 0, nmax}], x] Range[0, nmax]!] (* G. C. Greubel, Oct 07 2017 *)
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x='x+O('x^50); concat([0,0], Vec(serlaplace((1/3!)*(exp(7*x)-3*exp(4*x)-exp(3*x)+3*exp(2*x)+2*exp(x)-2)))) \\ G. C. Greubel, Oct 07 2017
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