A283572
T(n,k) = Number of n X k 0..1 arrays with no 1 equal to more than one of its horizontal, diagonal and antidiagonal neighbors, with the exception of exactly one element.
Original entry on oeis.org
0, 0, 0, 1, 4, 0, 2, 26, 16, 0, 5, 72, 169, 68, 0, 12, 282, 674, 1108, 256, 0, 26, 908, 4313, 6812, 6453, 924, 0, 56, 2832, 21186, 67892, 60802, 36038, 3232, 0, 118, 8856, 104464, 509952, 945100, 528436, 194173, 11044, 0, 244, 26750, 513458, 3890056, 10919674
Offset: 1
Some solutions for n=4, k=4
..1..1..0..0. .1..1..0..0. .0..0..0..0. .0..1..0..0. .0..0..1..0
..1..0..0..1. .0..0..0..1. .1..1..0..0. .1..0..0..0. .0..1..1..0
..0..0..1..0. .0..1..0..1. .1..0..1..0. .0..0..1..1. .1..0..0..0
..0..0..0..0. .0..1..1..0. .0..0..1..0. .1..0..0..1. .0..0..1..1
A282791
T(n,k)=Number of nXk 0..1 arrays with no 1 equal to more than one of its king-move neighbors, with the exception of exactly one element.
Original entry on oeis.org
0, 0, 0, 1, 0, 1, 2, 8, 8, 2, 5, 16, 73, 16, 5, 12, 72, 318, 318, 72, 12, 26, 240, 1747, 1952, 1747, 240, 26, 56, 736, 8216, 16584, 16584, 8216, 736, 56, 118, 2352, 38027, 119176, 208559, 119176, 38027, 2352, 118, 244, 7128, 173722, 832218, 2207352, 2207352
Offset: 1
Some solutions for n=4 k=4
..0..1..0..0. .0..1..0..1. .0..1..0..0. .0..0..1..1. .1..0..1..0
..1..0..0..1. .0..0..1..0. .1..0..0..1. .0..1..0..0. .0..0..1..0
..0..1..0..0. .1..0..0..0. .0..0..1..0. .0..0..0..1. .0..0..0..0
..0..0..0..0. .1..0..1..0. .1..0..0..1. .0..1..0..0. .1..1..1..0
A282885
T(n,k)=Number of nXk 0..1 arrays with no 1 equal to more than one of its horizontal, vertical and antidiagonal neighbors, with the exception of exactly one element.
Original entry on oeis.org
0, 0, 0, 1, 2, 1, 2, 8, 8, 2, 5, 32, 74, 32, 5, 12, 122, 430, 430, 122, 12, 26, 416, 2426, 3762, 2426, 416, 26, 56, 1414, 13062, 34314, 34314, 13062, 1414, 56, 118, 4626, 67676, 286920, 480995, 286920, 67676, 4626, 118, 244, 14930, 342972, 2342046, 6296324
Offset: 1
Some solutions for n=4 k=4
..0..0..1..0. .0..1..0..1. .0..1..1..1. .1..0..1..1. .0..1..0..0
..1..0..1..1. .0..0..0..0. .0..0..0..0. .1..0..0..0. .0..0..0..1
..0..0..0..0. .0..0..1..0. .1..0..0..0. .0..1..1..1. .0..0..1..0
..1..1..0..0. .0..0..1..1. .0..0..0..0. .0..0..0..0. .0..0..1..0
A283042
T(n,k)=Number of nXk 0..1 arrays with no 1 equal to more than one of its horizontal and vertical neighbors, with the exception of exactly one element.
Original entry on oeis.org
0, 0, 0, 1, 4, 1, 2, 16, 16, 2, 5, 68, 119, 68, 5, 12, 256, 818, 818, 256, 12, 26, 924, 5065, 9152, 5065, 924, 26, 56, 3232, 30378, 94368, 94368, 30378, 3232, 56, 118, 11044, 175963, 931844, 1604067, 931844, 175963, 11044, 118, 244, 37104, 997302, 8912378
Offset: 1
Some solutions for n=4 k=4
..0..0..1..0. .1..0..0..0. .1..0..1..0. .0..0..1..1. .1..0..0..1
..1..0..1..0. .1..1..0..0. .0..1..1..1. .0..1..0..0. .0..1..0..1
..0..0..1..0. .0..0..1..0. .1..0..1..0. .1..0..1..0. .0..1..0..1
..1..0..0..0. .1..0..1..0. .1..0..0..0. .1..1..0..0. .0..0..0..0
A118390
Triangle read by rows: T(n,k) is the number of binary sequences of length n containing k subsequences 000 (n, k >= 0).
Original entry on oeis.org
1, 2, 4, 7, 1, 13, 2, 1, 24, 5, 2, 1, 44, 12, 5, 2, 1, 81, 26, 13, 5, 2, 1, 149, 56, 29, 14, 5, 2, 1, 274, 118, 65, 32, 15, 5, 2, 1, 504, 244, 143, 74, 35, 16, 5, 2, 1, 927, 499, 307, 169, 83, 38, 17, 5, 2, 1, 1705, 1010, 652, 374, 196, 92, 41, 18, 5, 2, 1, 3136, 2027, 1369, 819
Offset: 0
T(6,2) = 5 because we have 000010, 000011, 010000, 100001 and 110000.
Triangle starts:
1;
2;
4;
7, 1;
13, 2, 1;
24, 5, 2, 1;
44, 12, 5, 2, 1;
81, 26, 13, 5, 2, 1;
-
G:=(1+(1-t)*z+(1-t)*z^2)/(1-(1+t)*z-(1-t)*z^2-(1-t)*z^3): Gser:=simplify(series(G,z=0,32)): P[0]:=1: for n from 1 to 13 do P[n]:=coeff(Gser,z^n) od: P[0]; P[1]; for n from 2 to 13 do seq(coeff(P[n],t,k),k=0..n-2) od; # yields sequence in triangular form
# second Maple program:
b:= proc(n, t) option remember; `if`(n=0, 1,
expand(b(n-1, min(2, t+1))*`if`(t>1, x, 1))+b(n-1, 0))
end:
T:= n-> (p-> seq(coeff(p, x, i), i=0..degree(p)))(b(n, 0)):
seq(T(n), n=0..14); # Alois P. Heinz, Sep 17 2019
-
nn=15;a=x^2/(1-y x)+x;b=1/(1-x);f[list_]:=Select[list,#>0&];Map[f,CoefficientList[Series[b (1+a)/(1-a x/(1-x)) ,{x,0,nn}],{x,y}]]//Grid (* Geoffrey Critzer, Nov 18 2012 *)
A118885
Number of binary sequences of length n containing exactly one subsequence 0011.
Original entry on oeis.org
0, 0, 0, 0, 1, 4, 12, 32, 78, 180, 400, 864, 1827, 3800, 7800, 15840, 31884, 63704, 126480, 249760, 490885, 960828, 1873828, 3642560, 7060314, 13649196, 26324704, 50662464, 97309767, 186571248, 357119472, 682524224, 1302589016, 2482706544
Offset: 0
a(5)=4 because we have 00110,00111,00011 and 10011.
-
g:=z^4/(1-2*z+z^4)^2: gser:=series(g,z=0,40): seq(coeff(gser,z,n),n=0..36);
A275445
Sum of the asymmetry degrees of all compositions of n with parts in {1,2,3}.
Original entry on oeis.org
0, 0, 0, 2, 4, 10, 22, 50, 106, 222, 458, 936, 1890, 3788, 7540, 14924, 29388, 57620, 112540, 219062, 425112, 822726, 1588314, 3059470, 5881254, 11284514, 21614774, 41336300, 78936358, 150533496, 286708744, 545428024, 1036468344, 1967555208, 3731449176, 7070218506, 13384916364, 25319020898, 47857031870, 90391975562, 170614347714
Offset: 0
a(4) = 4 because the compositions of 4 with parts in {1,2,3} are 13, 31, 22, 211, 121, 112, and 1111 and the sum of their asymmetry degrees is 1 + 1 + 0 + 1 + 0 + 1 + 0 = 4.
- S. Heubach and T. Mansour, Combinatorics of Compositions and Words, CRC Press, 2010.
- Colin Barker, Table of n, a(n) for n = 0..1000
- Krithnaswami Alladi and V. E. Hoggatt, Jr. Compositions with Ones and Twos, Fibonacci Quarterly, 13 (1975), 233-239.
- V. E. Hoggatt, Jr. and Marjorie Bicknell, Palindromic compositions, Fibonacci Quart., Vol. 13(4), 1975, pp. 350-356.
- Index entries for linear recurrences with constant coefficients, signature (1,2,2,0,-4,-6,-6,-3,-1).
-
g := 2*z^3*(1+z+z^2)/((1+z)*(1+z^2)*(1-z-z^2-z^3)^2): gser := series(g, z = 0, 45): seq(coeff(gser, z, n), n = 0 .. 40);
-
Table[Total@ Map[Total, Map[Map[Boole[# >= 1] &, BitXor[Take[# - 1, Ceiling[Length[#]/2]], ReverseTake[# - 1, -Ceiling[Length[#]/2]]]] &, Flatten[Map[Permutations, DeleteCases[IntegerPartitions@ n, {a_, _} /; a > 3]], 1]]], {n, 0, 24}] // Flatten (* Michael De Vlieger, Aug 17 2016 *)
-
concat(vector(3), Vec(2*x^3*(1+x+x^2)/((1+x)*(1+x^2)*(1-x-x^2-x^3)^2) + O(x^50))) \\ Colin Barker, Aug 28 2016
A383477
Square array A(n,k), n >= 0, k >= 0, read by antidiagonals downwards, where A(n,k) is the number of lattice paths from (0,0) to (n,k) using steps (1,0),(2,0),(3,0),(0,1).
Original entry on oeis.org
1, 1, 1, 1, 2, 2, 1, 3, 5, 4, 1, 4, 9, 12, 7, 1, 5, 14, 25, 26, 13, 1, 6, 20, 44, 63, 56, 24, 1, 7, 27, 70, 125, 153, 118, 44, 1, 8, 35, 104, 220, 336, 359, 244, 81, 1, 9, 44, 147, 357, 646, 864, 819, 499, 149, 1, 10, 54, 200, 546, 1134, 1800, 2144, 1830, 1010, 274
Offset: 0
Square array A(n,k) begins:
1, 1, 1, 1, 1, 1, 1, ...
1, 2, 3, 4, 5, 6, 7, ...
2, 5, 9, 14, 20, 27, 35, ...
4, 12, 25, 44, 70, 104, 147, ...
7, 26, 63, 125, 220, 357, 546, ...
13, 56, 153, 336, 646, 1134, 1862, ...
24, 118, 359, 864, 1800, 3395, 5950, ...
-
a(n, k) = my(x='x+O('x^(n+1)), y='y+O('y^(k+1))); polcoef(polcoef(1/(1-x-x^2-x^3-y), n), k);
A383474
Square array A(n,k), n >= 0, k >= 0, read by antidiagonals downwards, where A(n,k) is the number of lattice paths from (0,0) to (n,k) using steps (1,0),(2,0),(3,0),(0,1),(0,2),(0,3).
Original entry on oeis.org
1, 1, 1, 2, 2, 2, 4, 5, 5, 4, 7, 12, 14, 12, 7, 13, 26, 37, 37, 26, 13, 24, 56, 89, 106, 89, 56, 24, 44, 118, 209, 277, 277, 209, 118, 44, 81, 244, 477, 698, 784, 698, 477, 244, 81, 149, 499, 1063, 1700, 2113, 2113, 1700, 1063, 499, 149, 274, 1010, 2329, 4026, 5469, 6040, 5469, 4026, 2329, 1010, 274
Offset: 0
Square array A(n,k) begins:
1, 1, 2, 4, 7, 13, 24, ...
1, 2, 5, 12, 26, 56, 118, ...
2, 5, 14, 37, 89, 209, 477, ...
4, 12, 37, 106, 277, 698, 1700, ...
7, 26, 89, 277, 784, 2113, 5469, ...
13, 56, 209, 698, 2113, 6040, 16497, ...
24, 118, 477, 1700, 5469, 16497, 47332, ...
-
a(n, k) = my(x='x+O('x^(n+1)), y='y+O('y^(k+1))); polcoef(polcoef(1/(1-x-y-x^2-y^2-x^3-y^3), n), k);
A365330
Expansion of e.g.f. x^3/(1-x-x^2-x^3)^2.
Original entry on oeis.org
0, 0, 0, 6, 48, 600, 8640, 131040, 2257920, 42819840, 885427200, 19918483200, 483791616000, 12622171161600, 352200296448000, 10466625641472000, 330077933273088000, 11010660024139776000, 387369218691366912000, 14335266857678807040000, 556691771706962411520000
Offset: 0
a(6)=8640 since the ways to partition [6] into blocks of size at most 3, order the blocks, order the elements within each block, and select 3 elements from a block are the following:
(i) 123,4,5,6: 2880 such orderings, 1 way to choose three elements (from the block with 3 elements), hence 2880 ways;
(ii) 123,45,6: 4320 such orderings, 1 way to choose three elements (from the block with 3 elements), hence 4320 ways;
(iii) 123,456: 720 such orderings, 2 ways to choose three elements (from one of the two blocks with 3 elements), hence 1440 ways.
-
With[{m = 20}, Range[0, m]! * CoefficientList[Series[x^3/(1 - x - x^2 - x^3)^2, {x, 0, m}], x]] (* Amiram Eldar, Sep 02 2023 *)
Showing 1-10 of 10 results.
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