A192479
a(n) = 2^n*C(n-1) - A186997(n-1), where C(n) are the Catalan numbers (A000108).
Original entry on oeis.org
1, 3, 12, 61, 344, 2074, 13080, 85229, 569264, 3876766, 26817304, 187908802, 1330934032, 9513485076, 68539442800, 497178707325, 3628198048352, 26617955242806, 196205766112536, 1452410901340598, 10792613273706320
Offset: 1
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C := proc(n) binomial(2*n,n)/(n+1) ;end proc:
Yildf := proc(n) option remember; if n<=1 then 1; else add( (2^i*C(i-1)-procname(i))*procname(n-i),i=1..n-1) ; end if; end proc:
A192479 := proc(n) 2^n*C(n-1)-Yildf(n) ; end proc:
seq(A192479(n),n=1..30) ; # R. J. Mathar, Jul 13 2011
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a[1] = 1; a[n_] := 2^n*CatalanNumber[n-1] - Sum[Binomial[k, n-k-1]*Binomial[n+2*k-1, n+k-1]/(n+k), {k, 1, n-1}]; Table[a[n], {n, 1, 30}] (* Jean-François Alcover, Apr 02 2015 *)
A364475
G.f. satisfies A(x) = 1 + x*A(x)^3 + x^2*A(x)^3.
Original entry on oeis.org
1, 1, 4, 18, 94, 529, 3135, 19270, 121732, 785496, 5155167, 34304706, 230923653, 1569684910, 10759159000, 74281473504, 516089542684, 3605685460750, 25316226436086, 178538289189108, 1264131169628799, 8982889404251721, 64041351551534215
Offset: 0
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A364475 := proc(n)
add( binomial(3*n-3*k,k) * binomial(3*n-4*k,n-2*k)/(2*n-2*k+1),k=0..n/2) ;
end proc:
seq(A364475(n),n=0..80); # R. J. Mathar, Jul 27 2023
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a(n) = sum(k=0, n\2, binomial(3*n-3*k, k)*binomial(3*n-4*k, n-2*k)/(2*n-2*k+1));
A218045
Number of truth tables of bracketed formulas (case 3).
Original entry on oeis.org
0, 0, 1, 2, 9, 46, 262, 1588, 10053, 65686, 439658, 2999116, 20774154, 145726348, 1033125004, 7390626280, 53281906861, 386732675046, 2823690230850, 20725376703324, 152833785130398, 1131770853856100, 8412813651862868
Offset: 0
G.f. A(x) = x^2 + 2*x^3 + 9*x^4 + 46*x^5 + 262*x^6 + 1588*x^7 + 10053*x^8 + 65686*x^9 + 439658*x^10 + ...
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CoefficientList[Series[(2+2*Sqrt[1-8*x]-(1+Sqrt[1-8*x])*Sqrt[2+2*Sqrt[1-8*x]+8*x])/8, {x, 0, 20}], x] (* Vaclav Kotesovec, Nov 19 2014 after Yildiz *)
Flatten[{0,0,Table[Sum[(Sum[Binomial[k,2*k+i+2-n]*Binomial[k+i-1,i],{i,0,n-k-1}]*Binomial[2*n-2,k])/(n-1),{k,0,n-1}],{n,2,20}]}] (* Vaclav Kotesovec, Nov 19 2014 after Vladimir Kruchinin *)
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a(n):=sum((sum(binomial(k,2*k+i-n)*binomial(k+i-1,i),i,0,n-k+1))*binomial(2*n+2,k),k,0,n+1)/(n+1); /* Vladimir Kruchinin, Nov 19 2014 */
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x='x+O('x^50); concat([0,0], Vec((2+2*sqrt(1-8*x)-(1+sqrt(1-8*x))*sqrt(2 + 2*sqrt(1-8*x)+8*x))/8)) \\ G. C. Greubel, Apr 01 2017
A364474
G.f. satisfies A(x) = 1 + x*A(x)^3 + x^2*A(x).
Original entry on oeis.org
1, 1, 4, 16, 77, 403, 2228, 12800, 75653, 457022, 2809266, 17514200, 110480475, 703850686, 4522217364, 29268545416, 190645760149, 1248817411471, 8221323983431, 54365667330636, 360954069730636, 2405225494066647, 16080210766344354, 107828663888705292
Offset: 0
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A364474 := proc(n)
add( binomial(3*n-5*k,k) * binomial(3*n-6*k,n-2*k)/(2*n-4*k+1),k=0..n/2) ;
end proc:
seq(A364474(n),n=0..80); # R. J. Mathar, Jul 27 2023
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Table[Sum[Binomial[3*n - 5*k, k]*Binomial[3*n - 6*k, n - 2*k]/(2*n - 4*k + 1), {k, 0, Floor[n/2]}], {n, 0, 25}] (* Wesley Ivan Hurt, May 25 2024 *)
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a(n) = sum(k=0, n\2, binomial(3*n-5*k, k)*binomial(3*n-6*k, n-2*k)/(2*n-4*k+1));
A364478
G.f. satisfies A(x) = 1 + x*A(x)^3 + x^2*A(x)^8.
Original entry on oeis.org
1, 1, 4, 23, 154, 1124, 8675, 69626, 575243, 4859778, 41789764, 364565277, 3218581695, 28702642553, 258172627259, 2339496034381, 21337716782873, 195726876816623, 1804472496834650, 16711389876481027, 155395461519245354, 1450298253483719944
Offset: 0
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a(n) = sum(k=0, n\2, binomial(3*n+2*k, k)*binomial(3*n+k, n-2*k)/(2*n+3*k+1));
A378290
Square array T(n,k), n >= 0, k >= 0, read by antidiagonals downwards, where T(n,0) = 0^n and T(n,k) = k * Sum_{r=0..n} binomial(n+2*r+k,r) * binomial(r,n-r)/(n+2*r+k) for k > 0.
Original entry on oeis.org
1, 1, 0, 1, 1, 0, 1, 2, 4, 0, 1, 3, 9, 19, 0, 1, 4, 15, 46, 104, 0, 1, 5, 22, 82, 262, 614, 0, 1, 6, 30, 128, 486, 1588, 3816, 0, 1, 7, 39, 185, 789, 3027, 10053, 24595, 0, 1, 8, 49, 254, 1185, 5052, 19543, 65686, 162896, 0, 1, 9, 60, 336, 1689, 7801, 33290, 129606, 439658, 1101922, 0
Offset: 0
Square array begins:
1, 1, 1, 1, 1, 1, 1, ...
0, 1, 2, 3, 4, 5, 6, ...
0, 4, 9, 15, 22, 30, 39, ...
0, 19, 46, 82, 128, 185, 254, ...
0, 104, 262, 486, 789, 1185, 1689, ...
0, 614, 1588, 3027, 5052, 7801, 11430, ...
0, 3816, 10053, 19543, 33290, 52490, 78552, ...
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T(n, k, t=3, u=1) = if(k==0, 0^n, k*sum(r=0, n, binomial(t*r+u*(n-r)+k, r)*binomial(r, n-r)/(t*r+u*(n-r)+k)));
matrix(7, 7, n, k, T(n-1, k-1))
A192481
a(n) = Sum_{i=1..n-1} (2^i*C(i)-a(i)) * (2^(n-i)*C(n-i)-a(n-i)), a(1)=1, where C(i)=A000108(i-1) are Catalan numbers.
Original entry on oeis.org
1, 1, 6, 29, 162, 978, 6156, 40061, 267338, 1819238, 12576692, 88079378, 623581332, 4455663876, 32090099352, 232711721757, 1697799727066, 12452943237342, 91774314536100, 679234371006982, 5046438870909244, 37623611703611452, 281391143518722728
Offset: 1
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C := proc(n) binomial(2*n,n)/(n+1) ; end proc:
A192481 := proc(n) option remember; if n<=1 then n; else add( (2^i*C(i-1)-procname(i))*(2^(n-i)*C(n-i-1)-procname(n-i)), i=1..n-1) ; end if; end proc:
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CoefficientList[Series[(2 - Sqrt[1 - 8*x] - Sqrt[3 - 4*x - 2*Sqrt[1 - 8*x]])/2, {x,0,50}], x] (* G. C. Greubel, Feb 12 2017 *)
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x='x+O('x^50); Vec((2-sqrt(1-8*x)-sqrt(3-4*x-2*sqrt(1-8*x)))/2) \\ G. C. Greubel, Feb 12 2017
A367040
G.f. satisfies A(x) = 1 + x^2 + x*A(x)^3.
Original entry on oeis.org
1, 1, 4, 15, 70, 360, 1953, 11008, 63837, 378390, 2282205, 13960890, 86411232, 540166219, 3405341160, 21625820793, 138216775785, 888371346825, 5738510504979, 37234351046835, 242567430368298, 1585979835198675, 10403866383915844, 68453912880893025
Offset: 0
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a(n) = sum(k=0, n\2, binomial(2*(n-2*k)+1, k)*binomial(3*(n-2*k), n-2*k)/(2*(n-2*k)+1));
A218182
Number of truth tables of bracketed formulas (case 1).
Original entry on oeis.org
0, 0, 1, 6, 33, 194, 1198, 7676, 50581, 340682, 2335186, 16237284, 114255994, 812107412, 5822171548, 42052209400, 305714145869, 2235262899418, 16426616425002, 121265916776148, 898878250833358, 6687497426512700, 49920590244564484
Offset: 0
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my(x='x+O('x^30)); concat([0,0], Vec(((1-8*x)^(1/2)-3)*((2+2*(1-8*x)^(1/2)+8*x)^(1/2)-2)/8)) \\ Michel Marcus, Oct 21 2020
A240586
Expansion of (((8-8 / sqrt(1-8*x)) / (2*sqrt(8*x+2*sqrt(1-8*x)+2))+4 / sqrt(1-8*x))*((x*(sqrt(8*x+2*sqrt(1-8*x)+2)-sqrt(1-8*x)-1))-4*x^2)) / (sqrt(8*x+2*sqrt(1-8*x)+2)-sqrt(1-8*x)-1)^2.
Original entry on oeis.org
1, 4, 22, 140, 950, 6692, 48284, 354216, 2630310, 19713188, 148817524, 1130011896, 8621650492, 66043991080, 507628779896, 3913088587472, 30240258982662, 234210742764964, 1817484391184900, 14128074297880536, 109992814064010196, 857525947713607096, 6693820044841440008
Offset: 1
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Rest[CoefficientList[Series[(((8-8 / Sqrt[1-8*x]) / (2*Sqrt[8*x+2*Sqrt[1-8*x]+2])+4 / Sqrt[1-8*x])*((x*(Sqrt[8*x+2*Sqrt[1-8*x]+2]-Sqrt[1-8*x]-1))-4*x^2)) / (Sqrt[8*x+2*Sqrt[1-8*x]+2]-Sqrt[1-8*x]-1)^2, {x, 0, 20}], x]] (* Vaclav Kotesovec, Apr 12 2014 *)
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a(n):=sum((sum(j*(sum((binomial(k,n-k)*binomial(2*k+j-1,k+j-1)) / (k+j),k,1,n))*(-1)^(j-m)*binomial(m,j),j,0,m))*binomial(n-1,m-1),m,1,n);
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my(x='x+O('x^50)); Vec((((8-8 / sqrt(1-8*x)) / (2*sqrt(8*x+2*sqrt(1-8*x)+2))+4 / sqrt(1-8*x))*((x*(sqrt(8*x+2*sqrt(1-8*x)+2)-sqrt(1-8*x)-1))-4*x^2)) / (sqrt(8*x+2*sqrt(1-8*x)+2)-sqrt(1-8*x)-1)^2) \\ G. C. Greubel, Apr 05 2017
Showing 1-10 of 13 results.
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