A128079
a(n) = Sum_{k=0..n} A000984(k)*A001263(n+1,k+1), where A000984 is the central binomial coefficients and A001263 is the Narayana triangle.
Original entry on oeis.org
1, 3, 13, 69, 411, 2633, 17739, 124029, 892327, 6567285, 49235715, 374841195, 2890994445, 22545855855, 177524073021, 1409591810133, 11275693221519, 90792020672429, 735367765159347, 5987665336600683, 48987680485918149
Offset: 0
Illustrate a(n) = Sum_{k=0..n} A000984(k)*A001263(n+1,k+1) by:
a(2) = 1*(1) + 2*(3) + 6*(1) = 13;
a(3) = 1*(1) + 2*(6) + 6*(6) + 20*(1) = 69;
a(4) = 1*(1) + 2*(10)+ 6*(20)+ 20*(10)+ 70*(1) = 411.
The Narayana triangle A001263(n+1,k+1) = C(n,k)*C(n+1,k)/(k+1) begins:
1;
1, 1;
1, 3, 1;
1, 6, 6, 1;
1, 10, 20, 10, 1;
1, 15, 50, 50, 15, 1; ...
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Table[Sum[Binomial[2*k,k]*Binomial[n,k]*Binomial[n+1,k]/(k+1),{k,0,n}],{n,0,20}] (* Vaclav Kotesovec, Oct 20 2012 *)
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{a(n)=sum(k=0,n,binomial(2*k,k)*binomial(n,k)*binomial(n+1,k)/(k+1))}
Original entry on oeis.org
1, 1, 3, 1, 9, 6, 1, 18, 36, 10, 1, 30, 120, 100, 15, 1, 45, 300, 500, 225, 21, 1, 63, 630, 1750, 1575, 441, 28, 1, 84, 1176, 4900, 7350, 4116, 784, 36, 1, 108, 2016, 11760, 26460, 24696, 9408, 1296, 45, 1, 135, 3240, 25200, 79380, 111132, 70560, 19440
Offset: 1
First few rows of the triangle are:
1;
1, 3;
1, 9, 6;
1, 18, 36, 10;
1, 30, 120, 100, 15;
1, 45, 300, 500, 225, 21;
...
Original entry on oeis.org
1, 1, 3, 13, 44, 146, 530, 1975, 7314, 27262, 102802, 390138, 1486064, 5682756, 21812436, 83976075, 324115550, 1253795510, 4859960402, 18871869302, 73398851448, 285882923196, 1114943553308, 4353426835238, 17016813133124, 66581653586476, 260750813149140, 1022023318047220
Offset: 1
a(4) = 13 = (1, 6, 6, 1) dot (1, 0, 2, 0) = (1 + 0 + 12 + 0).
Triangle A001263(n,k) * A027656(k+1) and the rows sums:
1; : 1;
1, 0; : 1;
1, 0, 2; : 3;
1, 0, 12, 0; : 13;
1, 0, 40, 0, 3; : 44;
1, 0, 100, 0, 45, 0; : 146;
1, 0, 210, 0, 315, 0, 4; : 530;
1, 0, 392, 0, 1470, 0, 112, 0; : 1975;
1, 0, 672, 0, 5292, 0, 1344, 0, 5; : 7314;
1, 0, 1080, 0, 15876, 0, 10080, 0, 225, 0 : 27262;
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A136520:= func< n | (&+[((j+1)/(2*j+1))*Binomial(n,2*j)*Binomial(n-1,2*j): j in [0..Floor((n-1)/2)]]) >;
[A136520(n): n in [1..40]]; // G. C. Greubel, Jul 27 2023
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A136520[n_]:= Sum[Binomial[n-1, 2*k]*Binomial[n, 2*k]*((k+1)/(2*k+1)), {k,0,Floor[(n-1)/2]}];
Table[A136520[n], {n, 40}] (* G. C. Greubel, Jul 27 2023 *)
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def A136520(n): return sum(((j+1)/(2*j+1))*binomial(n,2*j)*binomial(n-1, 2*j) for j in range((n+1)//2))
[A136520(n) for n in range(1,41)] # G. C. Greubel, Jul 27 2023
Original entry on oeis.org
1, 2, 2, 4, 8, 3, 7, 24, 21, 4, 11, 60, 90, 44, 5, 16, 130, 300, 260, 80, 6, 22, 2252, 840, 1120, 630, 132, 7, 29, 448, 2058, 3920, 3430, 1344, 203, 8, 37, 744, 4536, 11760, 14700, 9072, 2604, 296, 9, 46, 1170, 9180, 31248, 52920, 46872, 21420, 4680, 414, 10
Offset: 1
First few rows of the triangle:
1;
2, 2;
4, 8, 3;
7, 24, 21, 4;
11, 60, 90, 44, 5;
16, 130, 300, 260, 80, 6;
22, 252, 840, 1120, 630, 132, 7;
...
Original entry on oeis.org
1, 1, 2, 1, 7, 3, 1, 15, 21, 4, 1, 26, 76, 46, 5, 1, 40, 200, 250, 85, 6, 1, 57, 435, 925, 645, 141, 7, 1, 77, 833, 2695, 3185, 1421, 217, 8, 1, 100, 1456, 6664, 11956, 9016, 2800, 316, 9, 1, 126, 2376, 14616, 37044, 42336, 22176, 5076, 441, 10
Offset: 1
First few rows of the triangle are:
1;
1, 2;
1, 7, 3;
1, 15, 21, 4;
1, 26, 76, 46, 5;
1, 40, 200, 250, 85, 6;
1, 57, 435, 925, 645, 141, 7;
...
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T4(n,k) = sum(j=k, n, binomial(n,j)*binomial(j,k)*(-1)^(j-k)*(j+1));
T3(n,k) = binomial(n, k)*binomial(n-1, k-1) - binomial(n, k-1)*binomial(n-1, k);
N=10; matrix(N, N, n, k, T4(n-1,k-1))*matrix(N, N,n,k,T3(n,k)) \\ Michel Marcus, Oct 11 2021
A143778
Eigentriangle of A001263, the Narayana triangle.
Original entry on oeis.org
1, 1, 1, 1, 3, 2, 1, 6, 12, 6, 1, 10, 40, 60, 25, 1, 15, 100, 300, 375, 136, 1, 21, 210, 1050, 2625, 2856, 927, 1, 18, 392, 2940, 12250, 26656, 25956, 7690, 1, 36, 672, 7056, 44100, 15993, 311472, 276840, 75913
Offset: 0
Triangle begins:
1;
1, 1;
1, 3, 2;
1, 6, 12, 6;
1, 10, 40, 60, 25;
1, 15, 100, 300, 375, 136;
1, 21, 210, 1050, 2625, 2856, 927;
...
Row 3 = (1, 6, 12, 6) = (1*1, 6*1, 6*2, 1*6) = termwise product of row 3 of the Narayana triangle: (1, 6, 6, 1) and the first 4 terms of the eigensequence of the Narayana triangle = (1, 1, 2, 6).
A155537
Triangle T(n,k,p,q) = (p^n + q^n)*A001263(n, k) with p=2 and q=1, read by rows.
Original entry on oeis.org
3, 5, 5, 9, 27, 9, 17, 102, 102, 17, 33, 330, 660, 330, 33, 65, 975, 3250, 3250, 975, 65, 129, 2709, 13545, 22575, 13545, 2709, 129, 257, 7196, 50372, 125930, 125930, 50372, 7196, 257, 513, 18468, 172368, 603288, 904932, 603288, 172368, 18468, 513
Offset: 1
Triangle begins as:
3;
5, 5;
9, 27, 9;
17, 102, 102, 17;
33, 330, 660, 330, 33;
65, 975, 3250, 3250, 975, 65;
129, 2709, 13545, 22575, 13545, 2709, 129;
257, 7196, 50372, 125930, 125930, 50372, 7196, 257;
513, 18468, 172368, 603288, 904932, 603288, 172368, 18468, 513;
1025, 46125, 553500, 2583000, 5424300, 5424300, 2583000, 553500, 46125, 1025;
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T:= func< n,k,p,q | (p^n + q^n)*Binomial(n-1, k-1)*Binomial(n, k)/(n-k+1) >;
[T(n,k,2,1): k in [1..n], n in [1..12]]; // G. C. Greubel, Mar 15 2021
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A155537:= (n,k,p,q)-> (p^n + q^n)*binomial(n-1, k-1)*binomial(n, k)/(n-k+1);
seq(seq(A155537(n,k,2,1), k=1..n), n=1..12); # G. C. Greubel, Mar 15 2021
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T[n_, k_, p_, q_]:= T[n,k,p,q]= (p^n + q^n)*Binomial[n-1, k-1]*Binomial[n, k]/(n-k+1);
Table[T[n,k,2,1], {n, 12}, {k, n}]//Flatten (* modified by G. C. Greubel, Mar 15 2021 *)
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def T(n,k,p,q): return (p^n + q^n)*binomial(n-1, k-1)*binomial(n, k)/(n-k+1)
flatten([[T(n,k,2,1) for k in (1..n)] for n in (1..12)]) # G. C. Greubel, Mar 15 2021
A157243
Triangle T(n, k) = A001263(n*f(n,k) + 1, f(n,k) + 1), where f(n, k) = k if k <= floor(n/2) otherwise n-k, read by rows.
Original entry on oeis.org
1, 1, 1, 1, 3, 1, 1, 6, 6, 1, 1, 10, 336, 10, 1, 1, 15, 825, 825, 15, 1, 1, 21, 1716, 197676, 1716, 21, 1, 1, 28, 3185, 512050, 512050, 3185, 28, 1, 1, 36, 5440, 1163800, 294296640, 1163800, 5440, 36, 1, 1, 45, 8721, 2395575, 778076145, 778076145, 2395575, 8721, 45, 1
Offset: 0
Triangle begins as:
1;
1, 1;
1, 3, 1;
1, 6, 6, 1;
1, 10, 336, 10, 1;
1, 15, 825, 825, 15, 1;
1, 21, 1716, 197676, 1716, 21, 1;
1, 28, 3185, 512050, 512050, 3185, 28, 1;
1, 36, 5440, 1163800, 294296640, 1163800, 5440, 36, 1;
1, 45, 8721, 2395575, 778076145, 778076145, 2395575, 8721, 45, 1;
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f:= func< n,k | k le Floor(n/2) select k else n-k >;
A001263:= func< n,k | Binomial(n-1,k-1)*Binomial(n,k)/(n-k+1) >;
[A001263(n*f(n,k)+1, f(n,k)+1): k in [0..n], n in [0..12]]; // G. C. Greubel, Jan 11 2022
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f[n_, k_]:= If[k<=Floor[n/2], k, n-k];
A001263[n_, k_]:= Binomial[n-1,k-1]*Binomial[n,k]/(n-k+1);
T[n_, k_]:= A001263[n*f[n,k] +1, f[n,k] +1];
Table[T[n, k], {n,0,12}, {k,0,n}]//Flatten (* modified by G. C. Greubel, Jan 11 2022 *)
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def f(n,k): return k if (k <= (n//2)) else n-k
def A001263(n,k): return binomial(n-1,k-1)*binomial(n,k)/(n-k+1)
flatten([[A001263(n*f(n,k)+1, f(n,k)+1) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Jan 11 2022
A168391
Triangle T(n, k) = [x^k]( p(n,x) ), where p(n, x) = Sum_{k=1..n} A001263(n,k)*binomial(x+k -1, n-1), read by rows.
Original entry on oeis.org
1, 1, 2, 2, 5, 5, 6, 19, 21, 14, 24, 84, 126, 84, 42, 120, 468, 750, 720, 330, 132, 720, 2988, 5496, 5445, 3795, 1287, 429, 5040, 22356, 43120, 50435, 35035, 19019, 5005, 1430, 40320, 186912, 391688, 472472, 398398, 208208, 92092, 19448, 4862
Offset: 1
Triangle begins as:
1;
1, 2;
2, 5, 5;
6, 19, 21, 14;
24, 84, 126, 84, 42;
120, 468, 750, 720, 330, 132;
720, 2988, 5496, 5445, 3795, 1287, 429;
5040, 22356, 43120, 50435, 35035, 19019, 5005, 1430;
40320, 186912, 391688, 472472, 398398, 208208, 92092, 19448, 4862;
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p[n_, x_]:= p[n,x]= ((-1)^(n+1)/(n+1))*Sum[Binomial[n-1, k-1]*Binomial[n+1, k]*Pochhammer[1-k-x, n-1], {k, n}];
A168391[n_]:= CoefficientList[p[x, n], x];
Table[A168391[n], {n,12}]//Flatten (* G. C. Greubel, Mar 28 2022 *)
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@CachedFunction
def p(n,x): return ((-1)^(n+1)/(n+1))*sum( binomial(n+1, k)*binomial(n-1, k-1)*rising_factorial(1-k-x, n-1) for k in (1..n) )
def A168391(n,k): return ( p(n,x) ).series(x, n+1).list()[k]
flatten([[A168391(n,k) for k in (0..n-1)] for n in (1..12)]) # G. C. Greubel, Mar 28 2022
A178655
Triangle which contains the first differences of the Catalan triangle A001263 constructed along rows.
Original entry on oeis.org
1, 1, -1, 1, 0, -1, 1, 2, -2, -1, 1, 5, 0, -5, -1, 1, 9, 10, -10, -9, -1, 1, 14, 35, 0, -35, -14, -1, 1, 20, 84, 70, -70, -84, -20, -1, 1, 27, 168, 294, 0, -294, -168, -27, -1, 1, 35, 300, 840, 588, -588, -840, -300, -35, -1
Offset: 0
Triangle begins
1;
1, -1;
1, 0, -1;
1, 2, -2, -1;
1, 5, 0, -5, -1;
1, 9, 10, -10, -9, -1;
1, 14, 35, 0, -35, -14, -1;
1, 20, 84, 70, -70, -84, -20, -1;
1, 27, 168, 294, 0, -294, -168, -27, -1;
1, 35, 300, 840, 588, -588, -840, -300, -35, -1;
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[[n le 0 select 1 else ((n+1)*(n-2*k)/(n*(k+1)*(n-k+1)))*Binomial(n, k)^2: k in [0..n]]: n in [0..10]]; // G. C. Greubel, Jan 28 2019
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Join[{1}, Table[((n+1)*(n-2*k)/(n*(k+1)*(n-k+1)))*Binomial[n, k]^2, {n, 1, 10}, {k, 0, n}]//Flatten] (* G. C. Greubel, Jan 28 2019 *)
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{T(n,k) = if(n==0, 1, ((n+1)*(n-2*k)/(n*(k+1)*(n-k+1)))* binomial(n, k)^2)};
for(n=0,10, for(k=0,n, print1(T(n,k), ", "))) \\ G. C. Greubel, Jan 28 2019
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[1] + [[((n+1)*(n-2*k)/(n*(k+1)*(n-k+1)))* binomial(n, k)^2 for k in (0..n)] for n in (1..10)] # G. C. Greubel, Jan 28 2019
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