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 1-9 of 9 results.

A256890 Triangle T(n,k) = t(n-k, k); t(n,m) = f(m)*t(n-1,m) + f(n)*t(n,m-1), where f(x) = x + 2.

Original entry on oeis.org

1, 2, 2, 4, 12, 4, 8, 52, 52, 8, 16, 196, 416, 196, 16, 32, 684, 2644, 2644, 684, 32, 64, 2276, 14680, 26440, 14680, 2276, 64, 128, 7340, 74652, 220280, 220280, 74652, 7340, 128, 256, 23172, 357328, 1623964, 2643360, 1623964, 357328, 23172, 256, 512, 72076, 1637860, 10978444, 27227908, 27227908, 10978444, 1637860, 72076, 512
Offset: 0

Views

Author

Dale Gerdemann, Apr 12 2015

Keywords

Comments

Related triangles may be found by varying the function f(x). If f(x) is a linear function, it can be parameterized as f(x) = a*x + b. With different values for a and b, the following triangles are obtained:
a\b 1.......2.......3.......4.......5.......6
The row sums of these, and similarly constructed number triangles, are shown in the following table:
a\b 1.......2.......3.......4.......5.......6.......7.......8.......9
The formula can be further generalized to: t(n,m) = f(m+s)*t(n-1,m) + f(n-s)*t(n,m-1), where f(x) = a*x + b. The following table specifies triangles with nonzero values for s (given after the slash).
a\b 0 1 2 3
-2 A130595/1
-1
0
With the absolute value, f(x) = |x|, one obtains A038221/3, A038234/4, A038247/5, A038260/6, A038273/7, A038286/8, A038299/9 (with value for s after the slash).
If f(x) = A000045(x) (Fibonacci) and s = 1, the result is A010048 (Fibonomial).
In the notation of Carlitz and Scoville, this is the triangle of generalized Eulerian numbers A(r, s | alpha, beta) with alpha = beta = 2. Also the array A(2,1,4) in the notation of Hwang et al. (see page 31). - Peter Bala, Dec 27 2019

Examples

			Array, t(n, k), begins as:
   1,    2,      4,        8,        16,         32,          64, ...;
   2,   12,     52,      196,       684,       2276,        7340, ...;
   4,   52,    416,     2644,     14680,      74652,      357328, ...;
   8,  196,   2644,    26440,    220280,    1623964,    10978444, ...;
  16,  684,  14680,   220280,   2643360,   27227908,   251195000, ...;
  32, 2276,  74652,  1623964,  27227908,  381190712,  4677894984, ...;
  64, 7340, 357328, 10978444, 251195000, 4677894984, 74846319744, ...;
Triangle, T(n, k), begins as:
    1;
    2,     2;
    4,    12,      4;
    8,    52,     52,       8;
   16,   196,    416,     196,      16;
   32,   684,   2644,    2644,     684,      32;
   64,  2276,  14680,   26440,   14680,    2276,     64;
  128,  7340,  74652,  220280,  220280,   74652,   7340,   128;
  256, 23172, 357328, 1623964, 2643360, 1623964, 357328, 23172,   256;
		

Crossrefs

Programs

  • Magma
    A256890:= func< n,k | (&+[(-1)^(k-j)*Binomial(j+3,j)*Binomial(n+4,k-j)*(j+2)^n: j in [0..k]]) >;
    [A256890(n,k): k in [0..n], n in [0..10]]; // G. C. Greubel, Oct 18 2022
    
  • Mathematica
    Table[Sum[(-1)^(k-j)*Binomial[j+3, j] Binomial[n+4, k-j] (j+2)^n, {j,0,k}], {n,0, 9}, {k,0,n}]//Flatten (* Michael De Vlieger, Dec 27 2019 *)
  • PARI
    t(n,m) = if ((n<0) || (m<0), 0, if ((n==0) && (m==0), 1, (m+2)*t(n-1, m) + (n+2)*t(n, m-1)));
    tabl(nn) = {for (n=0, nn, for (k=0, n, print1(t(n-k, k), ", ");); print(););} \\ Michel Marcus, Apr 14 2015
    
  • SageMath
    def A256890(n,k): return sum((-1)^(k-j)*Binomial(j+3,j)*Binomial(n+4,k-j)*(j+2)^n for j in range(k+1))
    flatten([[A256890(n,k) for k in range(n+1)] for n in range(11)]) # G. C. Greubel, Oct 18 2022

Formula

T(n,k) = t(n-k, k); t(0,0) = 1, t(n,m) = 0 if n < 0 or m < 0 else t(n,m) = f(m)*t(n-1,m) + f(n)*t(n,m-1), where f(x) = x + 2.
Sum_{k=0..n} T(n, k) = A001715(n).
T(n,k) = Sum_{j = 0..k} (-1)^(k-j)*binomial(j+3,j)*binomial(n+4,k-j)*(j+2)^n. - Peter Bala, Dec 27 2019
Modified rule of Pascal: T(0,0) = 1, T(n,k) = 0 if k < 0 or k > n else T(n,k) = f(n-k) * T(n-1,k-1) + f(k) * T(n-1,k), where f(x) = x + 2. - Georg Fischer, Nov 11 2021
From G. C. Greubel, Oct 18 2022: (Start)
T(n, n-k) = T(n, k).
T(n, 0) = A000079(n). (End)

A257609 Triangle read by rows: T(n,k) = t(n-k, k); t(n,m) = f(m)*t(n-1,m) + f(n)*t(n,m-1), where f(x) = 2*x + 2.

Original entry on oeis.org

1, 2, 2, 4, 16, 4, 8, 88, 88, 8, 16, 416, 1056, 416, 16, 32, 1824, 9664, 9664, 1824, 32, 64, 7680, 76224, 154624, 76224, 7680, 64, 128, 31616, 549504, 1999232, 1999232, 549504, 31616, 128, 256, 128512, 3739648, 22587904, 39984640, 22587904, 3739648, 128512, 256
Offset: 0

Views

Author

Dale Gerdemann, May 03 2015

Keywords

Examples

			Triangle begins as:
    1;
    2,      2;
    4,     16,       4;
    8,     88,      88,        8;
   16,    416,    1056,      416,       16;
   32,   1824,    9664,     9664,     1824,       32;
   64,   7680,   76224,   154624,    76224,     7680,      64;
  128,  31616,  549504,  1999232,  1999232,   549504,   31616,    128;
  256, 128512, 3739648, 22587904, 39984640, 22587904, 3739648, 128512, 256;
		

Crossrefs

Similar sequences listed in A256890.

Programs

  • Magma
    function T(n,k,a,b)
      if k lt 0 or k gt n then return 0;
      elif k eq 0 or k eq n then return 1;
      else return (a*k+b)*T(n-1,k,a,b) + (a*(n-k)+b)*T(n-1,k-1,a,b);
      end if; return T;
    end function;
    [T(n,k,2,2): k in [0..n], n in [0..12]]; // G. C. Greubel, Mar 21 2022
    
  • Magma
    A257609:= func< n,k | 2^n*EulerianNumber(n+1, k) >;
    [A257609(n,k): k in [0..n], n in [0..10]]; // G. C. Greubel, Jan 17 2025
    
  • Mathematica
    T[n_, k_, a_, b_]:= T[n, k, a, b]= If[k<0 || k>n, 0, If[n==0, 1, (a*(n-k)+b)*T[n-1, k-1, a, b] + (a*k+b)*T[n-1, k, a, b]]];
    Table[T[n,k,2,2], {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Mar 21 2022 *)
  • Sage
    def T(n,k,a,b): # A257609
        if (k<0 or k>n): return 0
        elif (n==0): return 1
        else: return  (a*k+b)*T(n-1,k,a,b) + (a*(n-k)+b)*T(n-1,k-1,a,b)
    flatten([[T(n,k,2,2) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Mar 21 2022

Formula

T(n,k) = t(n-k, k); t(0,0) = 1, t(n,m) = 0 if n < 0 or m < 0, else t(n,m) = f(m)*t(n-1,m) + f(n)*t(n,m-1), where f(x) = 2*x + 2.
Sum_{k=0..n} T(n, k) = A002866(n).
From G. C. Greubel, Mar 21 2022: (Start)
T(n, k) = (a*k + b)*T(n-1, k) + (a*(n-k) + b)*T(n-1, k-1), with T(n, 0) = 1, a = 2, and b = 2.
T(n, n-k) = T(n, k).
T(n, 0) = A000079(n).
T(n, 1) = 2*A100575(n+1). (End)
T(n, k) = 2^n*A008292(n+1, k+1). - G. C. Greubel, Jan 17 2025

A257610 Triangle read by rows: T(n,k) = t(n-k, k); t(n,m) = f(m)*t(n-1,m) + f(n)*t(n,m-1), where f(x) = 3*x + 2.

Original entry on oeis.org

1, 2, 2, 4, 20, 4, 8, 132, 132, 8, 16, 748, 2112, 748, 16, 32, 3964, 25124, 25124, 3964, 32, 64, 20364, 256488, 552728, 256488, 20364, 64, 128, 103100, 2398092, 9670840, 9670840, 2398092, 103100, 128, 256, 518444, 21246736, 147146804, 270783520, 147146804, 21246736, 518444, 256
Offset: 0

Views

Author

Dale Gerdemann, May 03 2015

Keywords

Examples

			Triangle begins as:
    1;
    2,      2;
    4,     20,        4;
    8,    132,      132,         8;
   16,    748,     2112,       748,        16;
   32,   3964,    25124,     25124,      3964,        32;
   64,  20364,   256488,    552728,    256488,     20364,       64;
  128, 103100,  2398092,   9670840,   9670840,   2398092,   103100,    128;
  256, 518444, 21246736, 147146804, 270783520, 147146804, 21246736, 518444, 256;
		

Crossrefs

See similar sequences listed in A256890.

Programs

  • Mathematica
    T[n_, k_, a_, b_]:= T[n, k, a, b]= If[k<0 || k>n, 0, If[n==0, 1, (a*(n-k)+b)*T[n-1, k-1, a, b] + (a*k+b)*T[n-1, k, a, b]]];
    Table[T[n,k,3,2], {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Mar 20 2022 *)
  • Sage
    def T(n,k,a,b): # A257610
        if (k<0 or k>n): return 0
        elif (n==0): return 1
        else: return  (a*k+b)*T(n-1,k,a,b) + (a*(n-k)+b)*T(n-1,k-1,a,b)
    flatten([[T(n,k,3,2) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Mar 20 2022

Formula

T(n,k) = t(n-k, k); t(0,0) = 1, t(n,m) = 0 if n < 0 or m < 0, else t(n,m) = f(m)*t(n-1,m) + f(n)*t(n,m-1), where f(x) = 3*x + 2.
Sum_{k=0..n} T(n, k) = A007559(n).
T(n, k) = (a*k + b)*T(n-1, k) + (a*(n-k) + b)*T(n-1, k-1), with T(n, 0) = 1, a = 3, and b = 2. - G. C. Greubel, Mar 20 2022

A257612 Triangle read by rows: T(n,k) = t(n-k, k); t(n,m) = f(m)*t(n-1,m) + f(n)*t(n,m-1), where f(x) = 4*x + 2.

Original entry on oeis.org

1, 2, 2, 4, 24, 4, 8, 184, 184, 8, 16, 1216, 3680, 1216, 16, 32, 7584, 53824, 53824, 7584, 32, 64, 46208, 674752, 1507072, 674752, 46208, 64, 128, 278912, 7764096, 33244544, 33244544, 7764096, 278912, 128, 256, 1677312, 84892672, 636233728, 1196803584, 636233728, 84892672, 1677312, 256
Offset: 0

Views

Author

Dale Gerdemann, May 06 2015

Keywords

Comments

Corresponding entries in this triangle and in A060187 differ only by powers of 2. - F. Chapoton, Nov 04 2020

Examples

			Triangle begins as:
    1;
    2,      2;
    4,     24,       4;
    8,    184,     184,        8;
   16,   1216,    3680,     1216,       16;
   32,   7584,   53824,    53824,     7584,      32;
   64,  46208,  674752,  1507072,   674752,   46208,     64;
  128, 278912, 7764096, 33244544, 33244544, 7764096, 278912, 128;
		

Crossrefs

Cf. A047053 (row sums), A060187, A142459, A257621.
See similar sequences listed in A256890.

Programs

  • Mathematica
    T[n_, k_, a_, b_]:= T[n, k, a, b]= If[k<0 || k>n, 0, If[n==0, 1, (a*(n-k)+b)*T[n-1, k-1, a, b] + (a*k+b)*T[n-1, k, a, b]]];
    Table[T[n,k,4,2], {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Mar 20 2022 *)
  • PARI
    f(x) = 4*x + 2;
    T(n, k) = t(n-k, k);
    t(n, m) = if (!n && !m, 1, if (n < 0 || m < 0, 0, f(m)*t(n-1,m) + f(n)*t(n,m-1)));
    tabl(nn) = for (n=0, nn, for (k=0, n, print1(T(n, k), ", ");); print();); \\ Michel Marcus, May 06 2015
    
  • Sage
    def T(n,k,a,b): # A257612
        if (k<0 or k>n): return 0
        elif (n==0): return 1
        else: return  (a*k+b)*T(n-1,k,a,b) + (a*(n-k)+b)*T(n-1,k-1,a,b)
    flatten([[T(n,k,4,2) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Mar 20 2022

Formula

T(n,k) = t(n-k, k); t(0,0) = 1, t(n,m) = 0 if n < 0 or m < 0, else t(n,m) = f(m)*t(n-1,m) + f(n)*t(n,m-1), where f(x) = 4*x + 2.
Sum_{k=0..n} T(n,k) = A047053(n).
T(n, k) = (a*k + b)*T(n-1, k) + (a*(n-k) + b)*T(n-1, k-1), with T(n, 0) = 1, a = 4, and b = 2. - G. C. Greubel, Mar 20 2022

A257616 Triangle read by rows: T(n,k) = t(n-k, k); t(n,m) = f(m)*t(n-1,m) + f(n)*t(n,m-1), where f(x) = 6*x + 2.

Original entry on oeis.org

1, 2, 2, 4, 32, 4, 8, 312, 312, 8, 16, 2656, 8736, 2656, 16, 32, 21664, 175424, 175424, 21664, 32, 64, 174336, 3019200, 7016960, 3019200, 174336, 64, 128, 1397120, 47847552, 218838400, 218838400, 47847552, 1397120, 128, 256, 11182592, 722956288, 5907889664, 11379596800, 5907889664, 722956288, 11182592, 256
Offset: 0

Views

Author

Dale Gerdemann, May 09 2015

Keywords

Examples

			Triangle begins as:
    1;
    2,       2;
    4,      32,        4;
    8,     312,      312,         8;
   16,    2656,     8736,      2656,        16;
   32,   21664,   175424,    175424,     21664,       32;
   64,  174336,  3019200,   7016960,   3019200,   174336,      64;
  128, 1397120, 47847552, 218838400, 218838400, 47847552, 1397120, 128;
		

Crossrefs

Cf. A000079, A049308 (row sums), A142461, A257625.
Similar sequences listed in A256890.

Programs

  • Mathematica
    T[n_, k_, a_, b_]:= T[n, k, a, b]= If[k<0 || k>n, 0, If[n==0, 1, (a*(n-k)+b)*T[n-1, k-1, a, b] + (a*k+b)*T[n-1, k, a, b]]];
    Table[T[n,k,6,2], {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Mar 21 2022 *)
  • Sage
    def T(n,k,a,b): # A257610
        if (k<0 or k>n): return 0
        elif (n==0): return 1
        else: return  (a*k+b)*T(n-1,k,a,b) + (a*(n-k)+b)*T(n-1,k-1,a,b)
    flatten([[T(n,k,6,2) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Mar 21 2022

Formula

T(n,k) = t(n-k, k); t(0,0) = 1, t(n,m) = 0 if n < 0 or m < 0, else t(n,m) = f(m)*t(n-1,m) + f(n)*t(n,m-1), where f(x) = 6*x + 2.
Sum_{k=0..n} T(n, k) = A049308(n).
From G. C. Greubel, Mar 21 2022: (Start)
T(n, k) = (a*k + b)*T(n-1, k) + (a*(n-k) + b)*T(n-1, k-1), with T(n, 0) = 1, a = 6, and b = 2.
T(n, n-k) = T(n, k).
T(n, 0) = A000079(n).
T(n, 1) = (2^n/3)*(2^(2*n+1) - (3*n+2)). (End)

A257617 Triangle read by rows: T(n,k) = t(n-k, k); t(n,m) = f(m)*t(n-1,m) + f(n)*t(n,m-1), where f(x) = 7*x + 2.

Original entry on oeis.org

1, 2, 2, 4, 36, 4, 8, 388, 388, 8, 16, 3676, 12416, 3676, 16, 32, 33564, 283204, 283204, 33564, 32, 64, 303260, 5538184, 13027384, 5538184, 303260, 64, 128, 2732156, 99831564, 465775352, 465775352, 99831564, 2732156, 128
Offset: 0

Views

Author

Dale Gerdemann, May 09 2015

Keywords

Examples

			    1;
    2,       2;
    4,      36,        4;
    8,     388,      388,         8;
   16,    3676,    12416,      3676,        16;
   32,   33564,   283204,    283204,     33564,       32;
   64,  303260,  5538184,  13027384,   5538184,   303260,      64;
  128, 2732156, 99831564, 465775352, 465775352, 99831564, 2732156, 128;
		

Crossrefs

Cf. A000079, A142462, A144827 (row sums), A257627.
Similar sequences listed in A256890.

Programs

  • Mathematica
    T[n_, k_, a_, b_]:= T[n, k, a, b]= If[k<0 || k>n, 0, If[n==0, 1, (a*(n-k)+b)*T[n-1, k-1, a, b] + (a*k+b)*T[n-1, k, a, b]]];
    Table[T[n,k,7,2], {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Mar 24 2022 *)
  • Sage
    def T(n,k,a,b): # A257617
        if (k<0 or k>n): return 0
        elif (n==0): return 1
        else: return  (a*k+b)*T(n-1,k,a,b) + (a*(n-k)+b)*T(n-1,k-1,a,b)
    flatten([[T(n,k,7,2) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Mar 24 2022

Formula

T(n,k) = t(n-k, k); t(0,0) = 1, t(n,m) = 0 if n < 0 or m < 0, else t(n,m) = f(m)*t(n-1,m) + f(n)*t(n,m-1), where f(x) = 7*x + 2.
Sum_{k=0..n} T(n, k) = A144827(n).
From G. C. Greubel, Mar 24 2022: (Start)
T(n, k) = (a*k + b)*T(n-1, k) + (a*(n-k) + b)*T(n-1, k-1), with T(n, 0) = 1, a = 7, and b = 2.
T(n, n-k) = T(n, k).
T(n, 0) = A000079(n).
T(n, 1) = (4*9^n - 2^n*(7*n + 4))/7.
T(n, 2) = (2^(n-1)*(49*n^2 +7*n -12) + 11*2^(4*n+1) - 4*(7*n+4)*9^n)/49. (End)

A257619 Triangle read by rows: T(n,k) = t(n-k, k); t(n,m) = f(m)*t(n-1,m) + f(n)*t(n,m-1), where f(x) = 9*x + 2.

Original entry on oeis.org

1, 2, 2, 4, 44, 4, 8, 564, 564, 8, 16, 6436, 22560, 6436, 16, 32, 71404, 637844, 637844, 71404, 32, 64, 786948, 15470232, 36994952, 15470232, 786948, 64, 128, 8660012, 346391196, 1660722424, 1660722424, 346391196, 8660012, 128
Offset: 0

Views

Author

Dale Gerdemann, May 09 2015

Keywords

Examples

			Triangle begins as:
    1;
    2,       2;
    4,      44,         4;
    8,     564,       564,          8;
   16,    6436,     22560,       6436,         16;
   32,   71404,    637844,     637844,      71404,        32;
   64,  786948,  15470232,   36994952,   15470232,    786948,      64;
  128, 8660012, 346391196, 1660722424, 1660722424, 346391196, 8660012, 128;
		

Crossrefs

Cf. A000079, A144829 (row sums), A257608.
Similar sequences listed in A256890.

Programs

  • Mathematica
    T[n_, k_, a_, b_]:= T[n, k, a, b]= If[k<0 || k>n, 0, If[n==0, 1, (a*(n-k)+b)*T[n-1, k-1, a, b] + (a*k+b)*T[n-1, k, a, b]]];
    Table[T[n,k,9,2], {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Mar 24 2022 *)
  • PARI
    f(x) = 9*x + 2;
    t(n, m) = if ((n<0) || (m<0), 0, if ((n==0) && (m==0), 1, f(m)*t(n-1,m) + f(n)*t(n,m-1)));
    tabl(nn) = {for (n=0, nn, for (k=0, n, print1(t(n-k, k), ", "); ); print(); ); } \\ Michel Marcus, May 23 2015
    
  • Sage
    def T(n,k,a,b): # A257619
        if (k<0 or k>n): return 0
        elif (n==0): return 1
        else: return  (a*k+b)*T(n-1,k,a,b) + (a*(n-k)+b)*T(n-1,k-1,a,b)
    flatten([[T(n,k,9,2) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Mar 24 2022

Formula

T(n,k) = t(n-k, k); t(0,0) = 1, t(n,m) = 0 if n < 0 or m < 0, else t(n,m) = f(m)*t(n-1,m) + f(n)*t(n,m-1), where f(x) = 9*x + 2.
Sum_{k=0..n} T(n, k) = A144829(n).
From G. C. Greubel, Mar 24 2022: (Start)
T(n, k) = (a*k + b)*T(n-1, k) + (a*(n-k) + b)*T(n-1, k-1), with T(n, 0) = 1, a = 9, and b = 2.
T(n, n-k) = T(n, k).
T(n, 0) = A000079(n).
T(n, 1) = (1/9)*(4*11^n - 2^n*(9*n + 4)).
T(n, 2) = (1/81)*(26*20^n - 4*(4+9*n)*11^n - 2^(n-1)*(20 + 9*n - 81*n^2)). (End)

A257618 Triangle read by rows: T(n,k) = t(n-k, k); t(n,m) = f(m)*t(n-1,m) + f(n)*t(n,m-1), where f(x) = 8*x + 2.

Original entry on oeis.org

1, 2, 2, 4, 40, 4, 8, 472, 472, 8, 16, 4928, 16992, 4928, 16, 32, 49824, 433984, 433984, 49824, 32, 64, 499584, 9505728, 22567168, 9505728, 499584, 64, 128, 4999040, 192085632, 909941120, 909941120, 192085632, 4999040, 128
Offset: 0

Views

Author

Dale Gerdemann, May 09 2015

Keywords

Examples

			Triangle begins as:
    1;
    2,       2;
    4,      40,         4;
    8,     472,       472,         8;
   16,    4928,     16992,      4928,        16;
   32,   49824,    433984,    433984,     49824,        32;
   64,  499584,   9505728,  22567168,   9505728,    499584,      64;
  128, 4999040, 192085632, 909941120, 909941120, 192085632, 4999040, 128;
		

Crossrefs

Cf. A000079, A144828 (row sums), A167884.
Similar sequences listed in A256890.

Programs

  • Mathematica
    T[n_, k_, a_, b_]:= T[n, k, a, b]= If[k<0 || k>n, 0, If[n==0, 1, (a*(n-k)+b)*T[n-1, k-1, a, b] + (a*k+b)*T[n-1, k, a, b]]];
    Table[T[n,k,8,2], {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Mar 24 2022 *)
  • Sage
    def T(n,k,a,b): # A257618
        if (k<0 or k>n): return 0
        elif (n==0): return 1
        else: return  (a*k+b)*T(n-1,k,a,b) + (a*(n-k)+b)*T(n-1,k-1,a,b)
    flatten([[T(n,k,8,2) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Mar 24 2022

Formula

T(n,k) = t(n-k, k); t(0,0) = 1, t(n,m) = 0 if n < 0 or m < 0, else t(n,m) = f(m)*t(n-1,m) + f(n)*t(n,m-1), where f(x) = 8*x + 2.
Sum_{k=0..n} T(n, k) = A144828(n).
From G. C. Greubel, Mar 24 2022: (Start)
T(n, k) = (a*k + b)*T(n-1, k) + (a*(n-k) + b)*T(n-1, k-1), with T(n, 0) = 1, a = 8, and b = 2.
T(n, n-k) = T(n, k).
T(n, 0) = A000079(n).
T(n, 1) = 2^(n-1)*(5^n - 2*n - 1).
T(n, 2) = 2^(n-3)*(3^(2*n+1) -2*(2*n+1)*5^n -1 +4*n^2). (End)

A257623 Triangle read by rows: T(n,k) = t(n-k, k), where t(n,m) = f(m)*t(n-1,m) + f(n)*t(n,m-1) and f(n) = 5*n + 3.

Original entry on oeis.org

1, 3, 3, 9, 48, 9, 27, 501, 501, 27, 81, 4494, 13026, 4494, 81, 243, 37815, 250230, 250230, 37815, 243, 729, 309324, 4122735, 9008280, 4122735, 309324, 729, 2187, 2498649, 62256627, 256971945, 256971945, 62256627, 2498649, 2187
Offset: 0

Views

Author

Dale Gerdemann, May 10 2015

Keywords

Examples

			Array, t(n,k), begins as:
    1,       3,         9,           27,             81, ... A000244;
    3,      48,       501,         4494,          37815, ...;
    9,     501,     13026,       250230,        4122735, ...;
   27,    4494,    250230,      9008280,      256971945, ...;
   81,   37815,   4122735,    256971945,    11820709470, ...;
  243,  309324,  62256627,   6368680566,   450199373658, ...;
  729, 2498649, 891791568, 144065371932, 15108742867890, ...;
Triangle, T(n,k), begins as:
     1;
     3,       3;
     9,      48,        9;
    27,     501,      501,        27;
    81,    4494,    13026,      4494,        81;
   243,   37815,   250230,    250230,     37815,      243;
   729,  309324,  4122735,   9008280,   4122735,   309324,     729;
  2187, 2498649, 62256627, 256971945, 256971945, 62256627, 2498649, 2187;
		

Crossrefs

Similar sequences listed in A256890.

Programs

  • Mathematica
    t[n_, k_, p_, q_]:= t[n, k, p, q]= If[n<0 || k<0, 0, If[n==0 && k==0, 1, (p*k+ q)*t[n-1,k,p,q] + (p*n+q)*t[n,k-1,p,q]]];
    T[n_, k_, p_, q_]= t[n-k,k,p,q];
    Table[T[n,k,5,3], {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Feb 27 2022 *)
  • Sage
    @CachedFunction
    def t(n,k,p,q):
        if (n<0 or k<0): return 0
        elif (n==0 and k==0): return 1
        else: return (p*k+q)*t(n-1,k,p,q) + (p*n+q)*t(n,k-1,p,q)
    def A257623(n,k): return t(n-k,k,5,3)
    flatten([[A257623(n,k) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Feb 27 2022

Formula

T(n,k) = t(n-k, k) where t(0,0) = 1, t(n,m) = 0 if n < 0 or m < 0, else t(n,m) = f(m)*t(n-1,m) + f(n)*t(n,m-1), and f(n) = 5*n + 3.
Sum_{k=0..n} T(n, k) = A008548(n).
From G. C. Greubel, Feb 27 2022: (Start)
t(k, n) = t(n, k).
T(n, n-k) = T(n, k).
t(0, n) = T(n, 0) = A000244(n). (End)
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