cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-3 of 3 results.

A082162 Number of deterministic completely defined initially connected acyclic automata with 3 inputs and n transient unlabeled states (and a unique absorbing state).

Original entry on oeis.org

1, 7, 139, 5711, 408354, 45605881, 7390305396, 1647470410551, 485292763088275, 183049273155939442, 86211400693272461866
Offset: 1

Views

Author

Valery A. Liskovets, Apr 09 2003

Keywords

Comments

Coefficients T_3(n,k) form the array A082170. These automata have no nontrivial automorphisms (by states).

References

  • R. Bacher, C. Reutenauer, The number of right ideals of given codimension over a finite field, in Noncommutative Birational Geometry, Representations and Combinatorics, edited by Arkady. Berenstein and Vladimir. Retakha, Contemporary Mathematics, Vol. 592, 2013.

Crossrefs

Programs

  • Mathematica
    T[n_, k_] := T[n, k] = If[nJean-François Alcover, Dec 15 2014 *)

Formula

a(n) = c_3(n)/(n-1)! where c_3(n) = T_3(n, 1) - sum(binomial(n-1, j-1)*T_3(n-j, j+1)*c_3(j), j=1..n-1) and T_3(0, k) = 1, T_3(n, k) = sum(binomial(n, i)*(-1)^(n-i-1)*(i+k)^(3*n-3*i)*T_3(i, k), i=0..n-1), n>0.
Equals column 0 of triangle A102098. Also equals main diagonal of A102400: a(n) = A102098(n, 0) = A102400(n, n). - Paul D. Hanna, Jan 07 2005

Extensions

More terms from Paul D. Hanna, Jan 07 2005

A082160 Deterministic completely defined acyclic automata with 3 inputs and n+1 transient labeled states including a unique state having all transitions to the absorbing state.

Original entry on oeis.org

1, 7, 315, 45682, 15646589, 10567689552, 12503979423607, 23841011541867520, 68835375121428936153, 286850872894190847235840, 1660638682341609286358474579, 12947089879912710544534553836032
Offset: 0

Views

Author

Valery A. Liskovets, Apr 09 2003

Keywords

Comments

This is the first column of the array A082172.

Crossrefs

Programs

  • Magma
    function a(n) // a = A082160
      if n eq 0 then return 1;
      else return (&+[Binomial(n,j)*(-1)^(n-j-1)*((j+2)^3 - 1)^(n-j)*a(j): j in [0..n-1]]);
      end if;
    end function;
    [a(n): n in [0..20]]; // G. C. Greubel, Jan 17 2024
    
  • Mathematica
    a[0] = 1; a[n_] := a[n] = Sum[Binomial[n, i] (-1)^(n - i - 1) ((i + 2)^3 - 1)^(n - i) a[i], {i, 0, n - 1}];
    Table[a[n], {n, 0, 11}] (* Jean-François Alcover, Aug 29 2019 *)
  • SageMath
    @CachedFunction
    def a(n): # A082160
        if n==0: return 1
        else: return sum(binomial(n,j)*(-1)^(n-j-1)*((j+2)^3 -1)^(n-j)*a(j) for j in range(n))
    [a(n) for n in range(21)] # G. C. Greubel, Jan 17 2024

Formula

a(n) = b_3(n) where b_3(0) = 1, b_3(n) = Sum_{i=0..n-1} binomial(n, i)*(-1)^(n-i-1)*((i+2)^3 - 1)^(n-i)*b_3(i), n > 0.

A082170 Deterministic completely defined quasi-acyclic automata with 3 inputs, n transient and k absorbing labeled states.

Original entry on oeis.org

1, 1, 1, 1, 8, 15, 1, 27, 368, 1024, 1, 64, 2727, 53672, 198581, 1, 125, 11904, 710532, 18417792, 85102056, 1, 216, 38375, 4975936, 386023509, 12448430408, 68999174203, 1, 343, 101520, 23945000, 3977848832, 381535651512, 14734002979456, 95264160938080
Offset: 0

Views

Author

Valery A. Liskovets, Apr 09 2003

Keywords

Comments

Array read by antidiagonals: (0,1),(0,2),(1,1),(0,3),...
The first column is A082158.

Examples

			The array begins:
            1,              1,               1,             1, ...;
            1,              8,              27,            64, ...;
           15,            368,            2727,         11904, ...;
         1024,          53672,          710532,       4975936, ...;
       198581,       18417792,       386023509,    3977848832, ...;
     85102056,    12448430408,    381535651512, 5451751738944, ...;
  68999174203, 14734002979456, 624245820664563, ...;
Antidiagonals begin as:
  1;
  1,   1;
  1,   8,    15;
  1,  27,   368,    1024;
  1,  64,  2727,   53672,    198581;
  1, 125, 11904,  710532,  18417792,    85102056;
  1, 216, 38375, 4975936, 386023509, 12448430408, 68999174203;
		

Crossrefs

Programs

  • Magma
    function A(n,k)
      if n eq 0 then return 1;
      else return (&+[(-1)^(n-j+1)*Binomial(n,j)*(k+j)^(3*n-3*j)*A(j,k): j in [0..n-1]]);
      end if;
    end function;
    A082170:= func< n,k | A(k,n-k+1) >;
    [A082170(n,k): k in [0..n], n in [0..12]]; // G. C. Greubel, Jan 19 2024
    
  • Mathematica
    T[0, ] = 1; T[n, k_]:= T[n, k] = Sum[Binomial[n, i] (-1)^(n-i-1)*(i + k)^(3n-3i) T[i, k], {i,0,n-1}];
    Table[T[n-k-1, k], {n, 1, 9}, {k, n-1, 1, -1}]//Flatten (* Jean-François Alcover, Aug 29 2019 *)
  • SageMath
    @CachedFunction
    def A(n,k):
        if n==0: return 1
        else: return sum((-1)^(n-j+1)*binomial(n,j)*(k+j)^(3*n-3*j)*A(j,k) for j in range(n))
    def A082170(n,k): return A(k,n-k+1)
    flatten([[A082170(n,k) for k in range(n+1)] for n in range(12)]) # G. C. Greubel, Jan 19 2024

Formula

T(n, k) = T_3(n, k) where T_3(0, k) = 1, T_3(n, k) = Sum_{i=0..n-1} (-1)^(n-i-1)*binomial(n, i)*(i+k)^(3*n-3*i)*T_3(i, k), n > 0.
Showing 1-3 of 3 results.