A190907
Triangle read by rows: T(n,k) = binomial(n+k, n-k) k! / (floor(k/2)! * floor((k+2)/2)!).
Original entry on oeis.org
1, 1, 1, 1, 3, 1, 1, 6, 5, 3, 1, 10, 15, 21, 2, 1, 15, 35, 84, 18, 10, 1, 21, 70, 252, 90, 110, 5, 1, 28, 126, 630, 330, 660, 65, 35, 1, 36, 210, 1386, 990, 2860, 455, 525, 14, 1, 45, 330, 2772, 2574, 10010, 2275, 4200, 238, 126
Offset: 0
[0] 1
[1] 1, 1
[2] 1, 3, 1
[3] 1, 6, 5, 3
[4] 1, 10, 15, 21, 2
[5] 1, 15, 35, 84, 18, 10
[6] 1, 21, 70, 252, 90, 110, 5
[7] 1, 28, 126, 630, 330, 660, 65, 35
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A190907 := (n,k) -> binomial(n+k,n-k)*k!/(floor(k/2)!*floor((k+2)/2)!);
seq(print(seq(A190907(n,k), k=0..n)), n=0..7);
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Flatten[Table[Binomial[n+k,n-k] k!/(Floor[k/2]!Floor[(k+2)/2]!),{n,0,10},{k,0,n}]] (* Harvey P. Dale, May 05 2012 *)
A101919
Triangle read by rows: T(n,k) is the number of Schroeder paths of length 2n and having k up steps starting at even heights.
Original entry on oeis.org
1, 1, 1, 1, 4, 1, 1, 12, 8, 1, 1, 33, 42, 13, 1, 1, 88, 183, 102, 19, 1, 1, 232, 717, 624, 205, 26, 1, 1, 609, 2622, 3275, 1650, 366, 34, 1, 1, 1596, 9134, 15473, 11020, 3716, 602, 43, 1, 1, 4180, 30691, 67684, 64553, 30520, 7483, 932, 53, 1, 1, 10945, 100284, 279106
Offset: 0
T(3,2)=8 because we have HU'DU'D, U'DHU'D, U'DU'DH, U'DU'HD, U'DU'UDD, U'HDU'D, U'UDDU'D and U'UU'DDD, the up steps starting at an even height being shown with a prime sign.
Triangle begins:
1;
1,1;
1,4,1;
1,12,8,1;
1,33,42,13,1;
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G:=1/2/(-z+z^2)*(-1+z+t*z-z^2+sqrt(1-6*z-2*t*z+11*z^2+2*t*z^2-6*z^3+t^2*z^2-2*t*z^3+z^4)): Gser:=simplify(series(G,z=0,13)): P[0]:=1: for n from 1 to 11 do P[n]:=coeff(Gser,z^n) od: for n from 0 to 11 do seq(coeff(t*P[n],t^k),k=1..n+1) od; # yields the sequence in triangular form
A144250
Eigentriangle, row sums = A125275, shifted.
Original entry on oeis.org
1, 1, 1, 1, 3, 2, 1, 6, 10, 6, 1, 10, 30, 42, 23, 1, 15, 70, 168, 207, 106, 1, 21, 140, 504, 1035, 1166, 567, 1, 28, 252, 1260, 3795, 6996, 7371, 3434
Offset: 0
First few rows of the triangle =
1;
1, 1;
1, 3, 2;
1, 6, 10, 6;
1, 10, 30, 42, 23;
1, 15, 70, 168, 207, 106;
1, 21, 140, 504, 1035, 1166, 567;
...
Row 4 = (1, 10, 30, 42, 23) = termwise products of (1, 10, 15, 7, 1) and (1, 1, 2, 6, 23) = (1*1, 10*1, 15*2, 7*6, 1*23); where (1, 10, 15, 7, 1) = row 4 of triangle A085478. Q
A155862
A 'Morgan Voyce' transform of A007854.
Original entry on oeis.org
1, 4, 22, 130, 790, 4870, 30274, 189202, 1186702, 7461982, 47007034, 296527162, 1872479350, 11833642006, 74833075570, 473463268642, 2996771766046, 18974162475598, 120167557286314, 761214481604554, 4822871486667526, 30561172252753030, 193682023673424226, 1227594333811376050, 7781431761074125486
Offset: 0
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R:=PowerSeriesRing(Rationals(), 30); Coefficients(R!( 2/(3*Sqrt(1-6*x+x^2) +x -1) )); // G. C. Greubel, Jun 04 2021
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CoefficientList[Series[2/(3*Sqrt[1-6*x+x^2]+x-1), {x, 0, 20}], x] (* Vaclav Kotesovec, Feb 01 2014 *)
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def A155862_list(prec):
P. = PowerSeriesRing(ZZ, prec)
return P( 2/(3*sqrt(1-6*x+x^2) +x-1) ).list()
A155862_list(30) # G. C. Greubel, Jun 04 2021
A155866
A 'Morgan Voyce' transform of the Bell numbers A000110.
Original entry on oeis.org
1, 2, 6, 22, 91, 413, 2032, 10754, 60832, 365815, 2327835, 15612872, 109992442, 811500784, 6253327841, 50211976959, 419239644142, 3632891419054, 32616077413970, 302915722319509, 2906047810600157, 28761123170398258, 293296874302640254, 3078390856651377534, 33220524976632438215
Offset: 0
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[(&+[Binomial(n+j,2*j)*Bell(j): j in [0..n]]): n in [0..30]]; // G. C. Greubel, Jun 10 2021
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A155866[n_]:= Sum[Binomial[n+j, 2*j]*BellB[j], {j,0,n}];
Table[A155866[n], {n, 0, 30}] (* G. C. Greubel, Jun 10 2021 *)
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def A155866(n): return sum( binomial(n+j, 2*j)*bell_number(j) for j in (0..n) )
[A155866(n) for n in (0..30)] # G. C. Greubel, Jun 10 2021
A155867
A 'Morgan Voyce' transform of the large Schroeder numbers A006318.
Original entry on oeis.org
1, 3, 13, 65, 355, 2061, 12501, 78323, 503033, 3294373, 21916883, 147708777, 1006330457, 6919474163, 47956087733, 334658965641, 2349535729811, 16583609673797, 117608812053277, 837626242775875, 5988634758319665
Offset: 0
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R:=PowerSeriesRing(Rationals(), 40); Coefficients(R!( (1-3*x+x^2 -Sqrt(1-10*x+19*x^2-10*x^3+x^4))/(2*x*(1-x)) )); // G. C. Greubel, Jun 09 2021
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A006318[n_]:= 2*Hypergeometric2F1[-n+1, n+2, 2, -1];
A155867[n_]:= Sum[Binomial[n+j, 2*j]*A006318[j], {j,0,n}];
Table[A155867[n], {n, 0, 40}] (* G. C. Greubel, Jun 09 2021 *)
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def A155867_list(prec):
P. = PowerSeriesRing(ZZ, prec)
return P( (1-3*x+x^2 -sqrt(1-10*x+19*x^2-10*x^3+x^4))/(2*x*(1-x)) ).list()
A155867_list(40) # G. C. Greubel, Jun 09 2021
A171824
Triangle T(n,k)= binomial(n + k,n) + binomial(2*n-k,n) read by rows.
Original entry on oeis.org
2, 3, 3, 7, 6, 7, 21, 14, 14, 21, 71, 40, 30, 40, 71, 253, 132, 77, 77, 132, 253, 925, 469, 238, 168, 238, 469, 925, 3433, 1724, 828, 450, 450, 828, 1724, 3433, 12871, 6444, 3048, 1452, 990, 1452, 3048, 6444, 12871, 48621, 24320, 11495, 5225, 2717, 2717, 5225, 11495, 24320, 48621
Offset: 0
Triangle begins as:
2;
3, 3;
7, 6, 7;
21, 14, 14, 21;
71, 40, 30, 40, 71;
253, 132, 77, 77, 132, 253;
925, 469, 238, 168, 238, 469, 925;
3433, 1724, 828, 450, 450, 828, 1724, 3433;
12871, 6444, 3048, 1452, 990, 1452, 3048, 6444, 12871;
48621, 24320, 11495, 5225, 2717, 2717, 5225, 11495, 24320, 48621;
184757, 92389, 43824, 19734, 9009, 6006, 9009, 19734, 43824, 92389, 184757;
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T:= func< n,k | Binomial(n+k,n) + Binomial(2*n-k,n) >;
[T(n,k): k in [0..n], n in [0..12]]; // G. C. Greubel, Apr 29 2021
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T[n_, k_] = Binomial[n+k, k] + Binomial[2*n-k, n-k];
Table[T[n, k], {n,0,10}, {k,0,n}]//Flatten
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def T(n, k): return binomial(n+k,n) + binomial(2*n-k,n)
flatten([[T(n,k) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Apr 29 2021
Formula and row sums reference added by the Assoc. Editors of the OEIS, Feb 24 2010
A185331
Riordan array ((1-x+x^2)/(1+x^2), x/(1+x^2)).
Original entry on oeis.org
1, -1, 1, 0, -1, 1, 1, -1, -1, 1, 0, 2, -2, -1, 1, -1, 1, 3, -3, -1, 1, 0, -3, 3, 4, -4, -1, 1, 1, -1, -6, 6, 5, -5, -1, 1, 0, 4, -4, -10, 10, 6, -6, -1, 1, -1, 1, 10, -10, -15, 15, 7, -7, -1, 1, 0, -5, 5, 20, -20, -21, 21, 8, -8, -1, 1
Offset: 0
Triangle begins:
1;
-1, 1;
0, -1, 1;
1, -1, -1, 1;
0, 2, -2, -1, 1;
-1, 1, 3, -3, -1, 1;
0, -3, 3, 4, -4, -1, 1;
1, -1, -6, 6, 5, -5, -1, 1;
0, 4, -4, -10, 10, 6, -6, -1, 1;
-1, 1, 10, -10, -15, 15, 7, -7, -1, 1;
0, -5, 5, 20, -20, -21, 21, 8, -8, -1, 1;
1, -1, -15, 15, 35, -35, -28, 28, 9, -9, -1, 1;
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CoefficientList[Series[CoefficientList[Series[(1 - x + x^2)/(1 - y*x + x^2), {x, 0, 10}], x], {y, 0, 10}], y] // Flatten (* G. C. Greubel, Jun 27 2017 *)
A206474
Riordan array ((1+x-x^2)/(1-x^2), x/(1-x^2)).
Original entry on oeis.org
1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 2, 2, 1, 1, 1, 1, 3, 3, 1, 1, 0, 3, 3, 4, 4, 1, 1, 1, 1, 6, 6, 5, 5, 1, 1, 0, 4, 4, 10, 10, 6, 6, 1, 1, 1, 1, 10, 10, 15, 15, 7, 7, 1, 1, 0, 5, 5, 20, 20, 21, 21, 8, 8, 1, 1, 1, 1, 15, 15, 35, 35, 28, 28, 9, 9, 1, 1
Offset: 0
Triangle begins :
1
1, 1
0, 1, 1
1, 1, 1, 1
0, 2, 2, 1, 1
1, 1, 3, 3, 1, 1
0, 3, 3, 4, 4, 1, 1
1, 1, 6, 6, 5, 5, 1, 1
0, 4, 4, 10, 10, 6, 6, 1, 1
1, 1, 10, 10, 15, 15, 7, 7, 1, 1
0, 5, 5, 20, 20, 21, 21, 8, 8, 1, 1
1, 1, 15, 15, 35, 35, 28, 28, 9, 9, 1, 1
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t[1, 0] = 1; t[2, 0] = 0; t[n_, n_] = 1; t[n_ /; n >= 0, k_ /; k >= 0] /; k <= n := t[n, k] = t[n-1, k-1] + t[n-2, k]; t[n_, k_] = 0; Table[t[n, k], {n, 0, 11}, {k, 0, n}] // Flatten (* Jean-François Alcover, Nov 28 2013 *)
A236376
Riordan array ((1-x+x^2)/(1-x)^2, x/(1-x)^2).
Original entry on oeis.org
1, 1, 1, 2, 3, 1, 3, 7, 5, 1, 4, 14, 16, 7, 1, 5, 25, 41, 29, 9, 1, 6, 41, 91, 92, 46, 11, 1, 7, 63, 182, 246, 175, 67, 13, 1, 8, 92, 336, 582, 550, 298, 92, 15, 1, 9, 129, 582, 1254, 1507, 1079, 469, 121, 17, 1, 10, 175, 957, 2508, 3718, 3367, 1925, 696, 154
Offset: 0
Triangle begins:
1;
1, 1;
2, 3, 1;
3, 7, 5, 1;
4, 14, 16, 7, 1;
5, 25, 41, 29, 9, 1;
6, 41, 91, 92, 46, 11, 1;
7, 63, 182, 246, 175, 67, 13, 1;
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# The function RiordanSquare is defined in A321620.
RiordanSquare(1+x/(1-x)^2, 8); # Peter Luschny, Mar 06 2022
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CoefficientList[#, y] & /@
CoefficientList[
Series[(1 - x + x^2)/(1 - 2*x - x*y + x^2), {x, 0, 12}], x] (* Wouter Meeussen, Jan 25 2014 *)
Comments