Original entry on oeis.org
1, 1, 2, 3, 5, 7, 12, 17, 30, 44, 79, 120, 218, 341, 625, 1001, 1848, 3016, 5603, 9283, 17342, 29085, 54606, 92513, 174456, 298111, 564333, 971563, 1845364, 3198130, 6092038, 10621153, 20282471, 35554559, 68042537, 119874494, 229840130, 406794862, 781246800, 1388643835
Offset: 0
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T[n_,k_]:=Sum[(-1)^j*Binomial[n,Floor[(n+(k+2)j)/2]],{j,Floor[-n/(k+2)],Ceiling[n/(k+2)]}]; Table[Sum[T[n-k,k],{k,0,n}],{n,0,39}]
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T(n,k) = sum(j=floor(-n/(k+2)), ceil(n/(k+2)), (-1)^j*binomial(n,floor((n+(k+2)*j)/2))); \\ A068914
a(n) = sum(k=0, n, T(n-k, k)); \\ Michel Marcus, May 09 2020
A216226
Square array T, read by antidiagonals: T(n,k) = 0 if n-k>=1 or if k-n>=4, T(0,0) = T(0,1) = T(0,2) = T(0,3) = 1, T(n,k) = T(n-1,k) + T(n,k-1).
Original entry on oeis.org
1, 1, 0, 1, 1, 0, 1, 2, 0, 0, 0, 3, 2, 0, 0, 0, 3, 5, 0, 0, 0, 0, 0, 8, 5, 0, 0, 0, 0, 0, 8, 13, 0, 0, 0, 0, 0, 0, 0, 21, 13, 0, 0, 0, 0, 0, 0, 0, 21, 34, 0, 0, 0, 0, 0, 0, 0, 0, 0, 55, 34, 0, 0, 0, 0, 0
Offset: 0
Square array begins:
1, 1, 1, 1, 0, 0, 0, 0, 0, 0, ... row n=0
0, 1, 2, 3, 3, 0, 0, 0, 0, 0, ... row n=1
0, 0, 2, 5, 8, 8, 0, 0, 0, 0, ... row n=2
0, 0, 0, 5, 13, 21, 21, 0, 0, 0, ... row n=3
0, 0, 0, 0, 13, 34, 55, 55, 0, 0, ... row n=4
0, 0, 0, 0, 0, 34, 89, 144, 144, 0, ... row n=5
...
A216228
Square array T, read by antidiagonals: T(n,k) = 0 if n-k>=1 or if k-n>=3, T(0,0) = T(0,1) = T(0,2) = 1, T(n,k) = T(n-1,k) + T(n,k-1).
Original entry on oeis.org
1, 1, 0, 1, 1, 0, 0, 2, 0, 0, 0, 2, 2, 0, 0, 0, 0, 4, 0, 0, 0, 0, 0, 4, 4, 0, 0, 0, 0, 0, 0, 8, 0, 0, 0, 0, 0, 0, 0, 8, 8, 0, 0, 0, 0, 0, 0, 0, 0, 16, 0, 0, 0, 0, 0, 0, 0, 0, 0, 16, 16, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 32, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 32, 32
Offset: 0
Square array begins:
1, 1, 1, 0, 0, 0, 0, 0, ... row n=0
0, 1, 2, 2, 0, 0, 0, 0, ... row n=1
0, 0, 2, 4, 4, 0, 0, 0, ... row n=2
0, 0, 0, 4, 8, 8, 0, 0, ... row n=3
0, 0, 0, 0, 8, 16, 16, 0, ... row n=4
0, 0, 0, 0, 0, 16, 32, 32, ... row n=5
...
- E. Lucas, Théorie des nombres, Albert Blanchard, Paris 1958, Tome 1, p.89
A216230
Square array T, read by antidiagonals: T(n,k) = 0 if n-k>=1 or if k-n>=2, T(0,0) = T(0,1) = 1, T(n,k) = T(n-1,k) + T(n,k-1).
Original entry on oeis.org
1, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0
Offset: 0
Square array begins:
1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ...
0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, ...
0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, ...
0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, ...
0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, ...
0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, ...
0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, ...
0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, ...
...
A132890
Triangle read by rows: T(n,k) is the number of left factors of Dyck paths of length n that have height k (1 <= k <= n).
Original entry on oeis.org
1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 3, 4, 1, 1, 1, 7, 5, 5, 1, 1, 1, 7, 13, 6, 6, 1, 1, 1, 15, 18, 20, 7, 7, 1, 1, 1, 15, 39, 26, 27, 8, 8, 1, 1, 1, 31, 57, 73, 35, 35, 9, 9, 1, 1, 1, 31, 112, 99, 109, 44, 44, 10, 10, 1, 1, 1, 63, 169, 253, 152, 154, 54, 54, 11, 11, 1, 1
Offset: 1
T(5,3)=4 because we have UDUUU, UUDUU, UUUDD and UUUDU, where U=(1,1) and D=(1,-1).
Triangle starts:
1;
1, 1;
1, 1, 1;
1, 3, 1, 1;
1, 3, 4, 1; 1;
1, 7, 5, 5, 1, 1;
- Alois P. Heinz, Rows n = 1..141, flattened
- Steven R. Finch, How far might we walk at random?, arXiv:1802.04615 [math.HO], 2018.
- R. Kemp, On the average depth of a prefix of the Dycklanguage D_1, Discrete Math., 36, 1981, 155-170.
- Toufik Mansour, Gokhan Yilidirim, Longest increasing subsequences in involutions avoiding patterns of length three, Turkish Journal of Mathematics (2019), Section 2.2
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v := ((1-sqrt(1-4*z^2))*1/2)/z: g := proc (k) options operator, arrow: v^k*(1+v)*(1+v^2)/((1+v^(k+1))*(1+v^(k+2))) end proc: T := proc (n, k) options operator, arrow: coeff(series(g(k), z = 0, 50), z, n) end proc: for n from 0 to 12 do seq(T(n, k), k = 1 .. n) end do; # yields sequence in triangular form
# second Maple program:
b:= proc(x, y, k) option remember; `if`(x=0, z^k, `if`(y>0,
b(x-2, y-1, k), 0)+ b(x-2, y+1, max(y+1, k)))
end:
T:= n-> (p-> seq(coeff(p, z, i), i=1..n))(b(2*n, 0$2)):
seq(T(n), n=1..16); # Alois P. Heinz, Sep 05 2017
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b[x_, y_, k_] := b[x, y, k] = If[x == 0, z^k, If[y > 0, b[x - 2, y - 1, k], 0] + b[x - 2, y + 1, Max[y + 1, k]]];
T[n_] := Function[p, Table[Coefficient[p, z, i], {i, 1, n}]][b[2n, 0, 0]];
Table[T[n], {n, 1, 16}] // Flatten (* Jean-François Alcover, Apr 01 2018, after Alois P. Heinz *)
A069713
As a square array T(n,k) by antidiagonals, number of ways of partitioning k into up to n parts each no more than 5, or into up to 5 parts each no more than n; as a triangle t(n,k), number of ways of partitioning n into exactly k parts each no more than 6 (i.e., of arranging k indistinguishable standard dice to produce a total of n).
Original entry on oeis.org
1, 0, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 2, 1, 1, 0, 1, 2, 2, 1, 1, 0, 1, 3, 3, 2, 1, 1, 0, 0, 3, 4, 3, 2, 1, 1, 0, 0, 3, 5, 5, 3, 2, 1, 1, 0, 0, 2, 6, 6, 5, 3, 2, 1, 1, 0, 0, 2, 6, 8, 7, 5, 3, 2, 1, 1, 0, 0, 1, 6, 9, 9, 7, 5, 3, 2, 1, 1, 0, 0, 1, 6, 11, 11, 10, 7, 5, 3, 2, 1, 1, 0, 0, 0, 5, 11, 14, 12, 10, 7, 5
Offset: 0
As square array, rows start: 1,0,0,0,0,0,...; 1,1,1,1,1,1,...; 1,1,2,2,3,3,...; 1,1,2,3,4,5,...; 1,1,2,3,5,6,...; 1,1,2,3,5,7,...; etc. As triangle, rows start: 1; 0,1; 0,1,1; 0,1,1,1; 0,1,2,1,1; 0,1,2,2,1,1; 0,1,3,3,2,1,1; etc. T(3,7)=6 since 7 can be written as 5+2, 5+1+1, 4+3, 4+2+1, 3+3+1, 3+2+2; or alternatively as 2+2+1+1+1, 3+1+1+1, 2+2+2+1, 3+2+1+1, 3+2+2, 3+3+1. t(10,3)=6 since 10 can be written as 6+3+1, 6+2+2, 5+4+1, 5+3+2, 4+4+2, 4+3+3.
Cf.
A061676 for a similar triangle, though with distinguishable dice (and a different offset). Antidiagonal sums of T(n, k), i.e., row sums (over k) of t(n, k), are
A001402. First 22 terms are same as
A068914 (see formula).
Showing 1-6 of 6 results.
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