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.

A022169 Triangle of Gaussian binomial coefficients [ n,k ] for q = 5.

Original entry on oeis.org

1, 1, 1, 1, 6, 1, 1, 31, 31, 1, 1, 156, 806, 156, 1, 1, 781, 20306, 20306, 781, 1, 1, 3906, 508431, 2558556, 508431, 3906, 1, 1, 19531, 12714681, 320327931, 320327931, 12714681, 19531, 1, 1, 97656, 317886556
Offset: 0

Views

Author

Keywords

Comments

The coefficients of the matrix inverse are apparently given by T^(-1)(n,k) = (-1)^n*A157832(n,k). - R. J. Mathar, Mar 12 2013

Examples

			Triangle begins:
  1;
  1,     1;
  1,     6,        1;
  1,    31,       31,         1;
  1,   156,      806,       156,         1;
  1,   781,    20306,     20306,       781,        1;
  1,  3906,   508431,   2558556,    508431,     3906,     1;
  1, 19531, 12714681, 320327931, 320327931, 12714681, 19531, 1,
		

References

  • F. J. MacWilliams and N. J. A. Sloane, The Theory of Error-Correcting Codes, Elsevier-North Holland, 1978, p. 698.
  • M. Sved, Gaussians and binomials, Ars. Combinatoria, 17A (1984), 325-351.

Crossrefs

Cf. A003462 (column k=1), A006111 (k=2), A006112 (k=3).
Row sums give A006119.

Programs

  • Maple
    A027872 := proc(n)
            mul( 5^i-1, i=1..n) ;
    end proc:
    A022169 := proc(n, m)
            A027872(n)/A027872(n-m)/A027872(m) ;
    end proc: # R. J. Mathar, Mar 12 2013
  • Mathematica
    p[n_] := Product[5^i-1, {i, 1, n}]; t[n_, k_] := p[n]/(p[k]*p[n-k]); Table[t[n, k], {n, 0, 8}, {k, 0, n}] // Flatten (* Jean-François Alcover, Jan 14 2014 *)
    Table[QBinomial[n,k,5], {n,0,10}, {k,0,n}]//Flatten (* or *) q:= 5; T[n_, 0]:= 1; T[n_,n_]:= 1; T[n_,k_]:= T[n,k] = If[k < 0 || n < k, 0, T[n-1, k -1] +q^k*T[n-1,k]]; Table[T[n,k], {n,0,10}, {k,0,n}] // Flatten  (* G. C. Greubel, May 27 2018 *)
  • PARI
    {q=5; T(n,k) = if(k==0,1, if (k==n, 1, if (k<0 || nG. C. Greubel, May 27 2018

Formula

T(n,k) = T(n-1,k-1) + q^k * T(n-1,k). - Peter A. Lawrence, Jul 13 2017
G.f. of column k: x^k * exp( Sum_{j>=1} f((k+1)*j)/f(j) * x^j/j ), where f(j) = 5^j - 1. - Seiichi Manyama, May 09 2025

A157783 Triangle read by rows: the coefficient [x^k] of the polynomial Product_{i=1..n} (3^(i-1)-x) in row n, column k, 0 <= k <= n.

Original entry on oeis.org

1, 1, -1, 3, -4, 1, 27, -39, 13, -1, 729, -1080, 390, -40, 1, 59049, -88209, 32670, -3630, 121, -1, 14348907, -21493836, 8027019, -914760, 33033, -364, 1, 10460353203, -15683355351, 5873190687, -674887059, 24995817, -298389, 1093
Offset: 0

Views

Author

Roger L. Bagula, Mar 06 2009

Keywords

Comments

Row sums except n=0 are zero.
Triangle T(n,k), 0 <= k <= n, read by rows given by [1,q-1,q^2,q^3-q,q^4,q^5-q^2,q^6,q^7-q^3,q^8,...] DELTA [ -1,0,-q,0,-q^2,0,-q^3,0,-q^4,0,...] (for q=3)=[1,2,9,24,81,234,729,2160,6561,...] DELTA [ -1,0,-3,0,-9,0,-27,0,-81,0,-243,0,...] where DELTA is the operator defined in A084938; see A122006 and A000244. - Philippe Deléham, Mar 09 2009

Examples

			Triangle begins
  1;
  1, -1;
  3, -4, 1;
  27, -39, 13, -1;
  729, -1080, 390, -40, 1;
  59049, -88209, 32670, -3630, 121, -1;
  14348907, -21493836, 8027019, -914760, 33033, -364, 1;
  10460353203, -15683355351, 5873190687, -674887059, 24995817, -298389, 1093, -1;
  22876792454961, -34309958505840, 12860351387820, -1481851188720, 55340738838, -677572560, 2688780, -3280, 1;
Row n=3 is 27 - 39*x + 13*x^2 - x^3.
		

Crossrefs

Cf. A157832, A135950, A022166, A047656 (column k=1), A003462 (subdiagonal k=n-1), A203243 (subdiagonal k=n-2).

Programs

  • Maple
    A157783 := proc(n,k)
        product( 3^(i-1)-x,i=1..n) ;
        coeftayl(%,x=0,k) ;
    end proc: # R. J. Mathar, Oct 15 2013
  • Mathematica
    Clear[f, q, M, n, m];
    q = 3;
    f[k_, m_] := If[k == m, q^(n - k), If[m == 1 && k < n, q^(n - k), If[k == n && m == 1, -(n-1), If[k == n && m > 1, 1, 0]]]];
    M[n_] := Table[f[k, m], {k, 1, n}, {m, 1, n}];
    Table[M[n], {n, 1, 10}];
    Join[{1}, Table[Expand[CharacteristicPolynomial[M[n], x]], {n, 1, 7}]];
    a = Join[{{ 1}}, Table[CoefficientList[CharacteristicPolynomial[M[n], x], x], {n, 1, 7}]];
    Flatten[a]

A157784 Triangle read by rows: the coefficient [x^k] of the polynomial Product_{i=1..n} (4^(i-1)-x), in row n and column 0 <= k <= n.

Original entry on oeis.org

1, 1, -1, 4, -5, 1, 64, -84, 21, -1, 4096, -5440, 1428, -85, 1, 1048576, -1396736, 371008, -23188, 341, -1, 1073741824, -1431306240, 381308928, -24115520, 372372, -1365, 1, 4398046511104, -5863704100864, 1563272675328, -99158478848
Offset: 0

Views

Author

Roger L. Bagula, Mar 06 2009

Keywords

Comments

Row sums except n=0 are zero.
The matrix inverses seem to be related to the Gaussian q-form combinations.
Triangle T(n,k), 0 <= k <= n, read by rows given by [1,q-1,q^2,q^3-q,q^4,q^5-q^2,q^6,q^7-q^3,q^8,...] DELTA [ -1,0,-q,0,-q^2,0,-q^3,0,-q^4,0,...] (for q=4)=[1,3,16,60,256,1008,4096,16320,65536,261888,...] DELTA [ -1,0,-4,0,-16,0,-64,0,-256,0,-1024,0,...] where DELTA is the operator defined in A084938. - Philippe Deléham, Mar 10 2009

Examples

			Triangle begins
  1;
  1, -1;
  4, -5, 1;
  64, -84, 21, -1;
  4096, -5440, 1428, -85, 1;
  1048576, -1396736, 371008, -23188, 341, -1;
  1073741824, -1431306240, 381308928, -24115520, 372372, -1365, 1;
  4398046511104, -5863704100864, 1563272675328, -99158478848, 1549351232, -5963412, 5461, -1;
  72057594037927936, -96075326035066880, 25618523216674816, -1626175790120960, 25483729063936, -99253893440, 95436436, -21845, 1;
Row n=3 represents 64 - 84*x + 21*x^2 - x^3.
		

Crossrefs

Programs

  • Maple
    A157784 := proc(n,k)
        product( 4^(i-1)-x,i=1..n) ;
        coeftayl(%,x=0,k) ;
    end proc: # R. J. Mathar, Oct 15 2013
  • Mathematica
    Clear[f, q, M, n, m];
    q = 4;
    f[k_, m_] := If[k == m, q^(n - k), If[m == 1 && k < n, q^(n - k), If[k == n && m == 1, -(n-1), If[k == n && m > 1, 1, 0]]]];
    M[n_] := Table[f[k, m], {k, 1, n}, {m, 1, n}];
    Table[M[n], {n, 1, 10}];
    Join[{1}, Table[Expand[CharacteristicPolynomial[M[n], x]], {n, 1, 7}]];
    a = Join[{{ 1}}, Table[CoefficientList[CharacteristicPolynomial[M[n], x], x], {n, 1, 7}]];
    Flatten[a]

A157963 Triangle T(n,k), 0<=k<=n, read by rows given by [1,q-1,q^2,q^3-q,q^4,q^5-q^2,q^6,q^7-q^3,q^8,...] DELTA [ -1,0,-q,0,-q^2,0,-q^3,0,-q^4,0,-q^5,0,...] (for q=2) = [1,1,4,6,16,28,64,...] DELTA [ -1,0,-2,0,-4,0,-8,0,-16,0,...] where DELTA is the operator defined in A084938.

Original entry on oeis.org

1, 1, -1, 2, -3, 1, 8, -14, 7, -1, 64, -120, 70, -15, 1, 1024, -1984, 1240, -310, 31, -1, 32768, -64512, 41664, -11160, 1302, -63, 1, 2097152, -4161536, 2731008, -755904, 94488, -5334, 127, -1, 268435456, -534773760, 353730560, -99486720, 12850368
Offset: 0

Views

Author

Philippe Deléham, Mar 10 2009

Keywords

Comments

Row sums equal 0^n.
Row n contains the coefficients of Product_{j=0..n-1} (2^j*x-1), highest coefficient first. - Alois P. Heinz, Mar 26 2012
The elements of the matrix inverse are apparently given by T^(-1)(n,k) = (-1)^k*A022166(n,k). - R. J. Mathar, Mar 26 2013

Examples

			Triangle begins :
1;
1,    -1;
2,    -3,  1;
8,   -14,  7,  -1;
64, -120, 70, -15,  1;
		

Crossrefs

Programs

  • Maple
    T:= n-> seq (coeff (mul (2^j*x-1, j=0..n-1), x, n-k), k=0..n):
    seq (T(n), n=0..10);  # Alois P. Heinz, Mar 26 2012
  • Mathematica
    row[n_] := CoefficientList[(-1)^n QPochhammer[x, 2, n] + O[x]^(n+1), x] // Reverse; Table[row[n], {n, 0, 10}] // Flatten (* Jean-François Alcover, May 26 2016 *)

Formula

T(n,k) = (-1)^n*A135950(n,k). T(n,0) = A006125(n).
T(n,k) = [x^(n-k)] Product_{j=0..n-1} (2^j*x-1). - Alois P. Heinz, Mar 26 2012
Showing 1-4 of 4 results.