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 1-4 of 4 results.

A172358 Triangle read by rows: T(n,k) = round(c(n)/(c(k)*c(n-k))) where c are partial products of a sequence defined in comments.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 3, 3, 1, 1, 3, 9, 9, 3, 1, 1, 5, 15, 45, 15, 5, 1, 1, 9, 45, 135, 135, 45, 9, 1, 1, 11, 99, 495, 495, 495, 99, 11, 1, 1, 19, 209, 1881, 3135, 3135, 1881, 209, 19, 1, 1, 29, 551, 6061, 18183, 30305, 18183, 6061, 551, 29, 1
Offset: 0

Views

Author

Roger L. Bagula, Feb 01 2010

Keywords

Comments

Start from the sequence A159284 and its partial products c(n) = 1, 1, 1, 1, 3, 9, 45, 405, 4455, 84645, 2454705, ... . Then T(n,k) = round( c(n)/(c(k)*c(n-k)) ).

Examples

			Triangle begins as:
  1;
  1,  1;
  1,  1,   1;
  1,  1,   1,    1;
  1,  3,   3,    3,     1;
  1,  3,   9,    9,     3,     1;
  1,  5,  15,   45,    15,     5,     1;
  1,  9,  45,  135,   135,    45,     9,    1;
  1, 11,  99,  495,   495,   495,    99,   11,   1;
  1, 19, 209, 1881,  3135,  3135,  1881,  209,  19,  1;
  1, 29, 551, 6061, 18183, 30305, 18183, 6061, 551, 29, 1;
		

Crossrefs

Cf. A172353 (q=1), this sequence (q=2), A172359 (q=4), A172360 (q=5).

Programs

  • Mathematica
    f[n_, q_]:= f[n, q]= If[n<3, Fibonacci[n], f[n-2, q] + q*f[n-3, q]];
    c[n_, q_]:= Product[f[j, q], {j,n}];
    T[n_, k_, q_]:= Round[c[n, q]/(c[k, q]*c[n-k, q])];
    Table[T[n, k, 2], {n,0,12}, {k,0,n}]//Flatten (* modified by G. C. Greubel, May 09 2021 *)
  • Sage
    @CachedFunction
    def f(n,q): return fibonacci(n) if (n<3) else f(n-2, q) + q*f(n-3, q)
    def c(n,q): return product( f(j,q) for j in (1..n) )
    def T(n,k,q): return round(c(n, q)/(c(k, q)*c(n-k, q)))
    flatten([[T(n,k,2) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, May 09 2021

Formula

T(n, k, q) = round(c(n,q)/(c(k,q)*c(n-k,q))), where c(n,q) = Product_{j=1..n} f(j,q), f(n, q) = f(n-2, q) + q*f(n-3, q), f(0,q) = 0, f(1,q) = f(2,q) = 1, and q = 2. - G. C. Greubel, May 09 2021

Extensions

Definition corrected to give integral terms by G. C. Greubel, May 09 2021

A172359 Triangle read by rows: T(n,k) = round(c(n)/(c(k)*c(n-k))) where c are partial products of a sequence defined in comments.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 5, 5, 5, 1, 1, 5, 25, 25, 5, 1, 1, 9, 45, 225, 45, 9, 1, 1, 25, 225, 1125, 1125, 225, 25, 1, 1, 29, 725, 6525, 6525, 6525, 725, 29, 1, 1, 61, 1769, 44225, 79605, 79605, 44225, 1769, 61, 1, 1, 129, 7869, 228201, 1141005, 2053809, 1141005, 228201, 7869, 129, 1
Offset: 0

Views

Author

Roger L. Bagula, Feb 01 2010

Keywords

Comments

Start from the sequence 0, 1, 1, 1, 5, 5, 9, 25, 29, 61, 129, 177, 373, 693, 1081, 2185, 3853, ..., f(n) = f(n-2) + 4*f(n-3) and its partial products c(n) = 1, 1, 1, 1, 5, 25, 225, 5625, 163125, 9950625, ... . Then T(n,k) = round(c(n)/(c(k)*c(n-k))).

Examples

			Triangle begins as:
  1;
  1,   1;
  1,   1,    1;
  1,   1,    1,      1;
  1,   5,    5,      5,       1;
  1,   5,   25,     25,       5,       1;
  1,   9,   45,    225,      45,       9,       1;
  1,  25,  225,   1125,    1125,     225,      25,      1;
  1,  29,  725,   6525,    6525,    6525,     725,     29,    1;
  1,  61, 1769,  44225,   79605,   79605,   44225,   1769,   61,   1;
  1, 129, 7869, 228201, 1141005, 2053809, 1141005, 228201, 7869, 129, 1;
		

Crossrefs

Cf. A172353 (q=1), A172358 (q=2), this sequence (q=4), A172360 (q=5).

Programs

  • Mathematica
    f[n_, q_]:= f[n, q]= If[n<3, Fibonacci[n], f[n-2, q] + q*f[n-3, q]];
    c[n_, q_]:= Product[f[j, q], {j,n}];
    T[n_, k_, q_]:= Round[c[n, q]/(c[k, q]*c[n-k, q])];
    Table[T[n, k, 4], {n,0,12}, {k,0,n}]//Flatten (* modified by G. C. Greubel, May 09 2021 *)
  • Sage
    @CachedFunction
    def f(n,q): return fibonacci(n) if (n<3) else f(n-2, q) + q*f(n-3, q)
    def c(n,q): return product( f(j,q) for j in (1..n) )
    def T(n,k,q): return round(c(n, q)/(c(k, q)*c(n-k, q)))
    flatten([[T(n,k,4) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, May 09 2021

Formula

T(n, k, q) = round(c(n,q)/(c(k,q)*c(n-k,q))), where c(n,q) = Product_{j=1..n} f(j,q), f(n, q) = f(n-2, q) + q*f(n-3, q), f(0,q) = 0, f(1,q) = f(2,q) = 1, and q = 4. - G. C. Greubel, May 09 2021

Extensions

Definition corrected to give integral terms by G. C. Greubel, May 09 2021

A172360 Triangle read by rows: T(n,k) = round(c(n)/(c(k)*c(n-k))) where c are partial products of a sequence defined in comments.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 6, 6, 6, 1, 1, 6, 36, 36, 6, 1, 1, 11, 66, 396, 66, 11, 1, 1, 36, 396, 2376, 2376, 396, 36, 1, 1, 41, 1476, 16236, 16236, 16236, 1476, 41, 1, 1, 91, 3731, 134316, 246246, 246246, 134316, 3731, 91, 1, 1, 221, 20111, 824551, 4947306, 9070061, 4947306, 824551, 20111, 221, 1
Offset: 0

Views

Author

Roger L. Bagula, Feb 01 2010

Keywords

Comments

Start from the sequence 0, 1, 1, 1, 6, 6, 11, 36, 41, 91, 221, 296, 676, 1401, 2156, ..., f(n) = f(n-2) + 5*f(n-3), and its partial products c(n) = 1, 1, 1, 1, 6, 36, 396, 14256, 584496, 53189136, ... . Then T(n,k) = round(c(n)/(c(k)*c(n-k))).

Examples

			Triangle begins as:
  1;
  1,   1;
  1,   1,     1;
  1,   1,     1,      1;
  1,   6,     6,      6,       1;
  1,   6,    36,     36,       6,       1;
  1,  11,    66,    396,      66,      11,       1;
  1,  36,   396,   2376,    2376,     396,      36,      1;
  1,  41,  1476,  16236,   16236,   16236,    1476,     41,     1;
  1,  91,  3731, 134316,  246246,  246246,  134316,   3731,    91,   1;
  1, 221, 20111, 824551, 4947306, 9070061, 4947306, 824551, 20111, 221, 1;
		

Crossrefs

Cf. A172353 (q=1), A172358 (q=2), A172359 (q=4), this sequence (q=5).

Programs

  • Mathematica
    f[n_, q_]:= f[n, q]= If[n<3, Fibonacci[n], f[n-2, q] + q*f[n-3, q]];
    c[n_, q_]:= Product[f[j, q], {j,n}];
    T[n_, k_, q_]:= Round[c[n, q]/(c[k, q]*c[n-k, q])];
    Table[T[n, k, 5], {n,0,12}, {k,0,n}]//Flatten (* modified by G. C. Greubel, May 09 2021 *)
  • Sage
    @CachedFunction
    def f(n,q): return fibonacci(n) if (n<3) else f(n-2, q) + q*f(n-3, q)
    def c(n,q): return product( f(j,q) for j in (1..n) )
    def T(n,k,q): return round(c(n, q)/(c(k, q)*c(n-k, q)))
    flatten([[T(n,k,5) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, May 09 2021

Formula

T(n, k, q) = round(c(n,q)/(c(k,q)*c(n-k,q))), where c(n,q) = Product_{j=1..n} f(j,q), f(n, q) = f(n-2, q) + q*f(n-3, q), f(0,q) = 0, f(1,q) = f(2,q) = 1, and q = 5. - G. C. Greubel, May 09 2021

Extensions

Definition corrected to give integral terms by G. C. Greubel, May 09 2021

A172355 Triangle t(n,k) read by rows: generalized Padovan factorial ratios c(n)/(c(k)*c(n-k)) where c are partial products of a generalized Padovan sequence with multiplier m=5.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 5, 5, 1, 1, 6, 30, 6, 1, 1, 26, 156, 156, 26, 1, 1, 35, 910, 1092, 910, 35, 1, 1, 136, 4760, 24752, 24752, 4760, 136, 1, 1, 201, 27336, 191352, 829192, 191352, 27336, 201, 1, 1, 715, 143715, 3909048, 22802780, 22802780, 3909048, 143715, 715
Offset: 0

Views

Author

Roger L. Bagula, Feb 01 2010

Keywords

Comments

Start from the generalized Padovan sequence f(n) = 0, 1, 1, 5, 6, 26, 35, 136, 201, 715, 1141, 3776,.. , f(n) = 5*f(n-2)+f(n-3), and its partial products c(n) = 1, 1, 1, 5, 30, 780, 27300, 3712800, 746272800, 533585052000.. Then t(n,k) = c(n)/(c(k)*c(n-k)).
Row sums are 1, 2, 3, 12, 44, 366, 2984, 59298, 1266972, 53712518, 2554657926,....
Note that rows n>= 14 contain fractions. - R. J. Mathar, Jul 05 2012

Examples

			1;
1, 1;
1, 1, 1;
1, 5, 5, 1;
1, 6, 30, 6, 1;
1, 26, 156, 156, 26, 1;
1, 35, 910, 1092, 910, 35, 1;
1, 136, 4760, 24752, 24752, 4760, 136, 1;
1, 201, 27336, 191352, 829192, 191352, 27336, 201, 1;
1, 715, 143715, 3909048, 22802780, 22802780, 3909048, 143715, 715, 1;
1, 1141, 815815, 32795763, 743370628, 1000691230, 743370628, 32795763, 815815, 1141, 1;
		

Crossrefs

Programs

  • Mathematica
    Clear[f, c, a, t];
    f[0, a_] := 0; f[1, a_] := 1; f[2, a_] := 1;
    f[n_, a_] := f[n, a] = a*f[n - 2, a] + f[n - 3, a];
    c[n_, a_] := If[n == 0, 1, Product[f[i, a], {i, 1, n}]];
    t[n_, m_, a_] := c[n, a]/(c[m, a]*c[n - m, a]);
    Table[Table[Table[t[n, m, a], {m, 0, n}], {n, 0, 10}], {a, 1, 10}];
    Table[Flatten[Table[Table[t[n, m, a], {m, 0, n}], {n, 0, 10}]], {a, 1, 10}]
Showing 1-4 of 4 results.