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.

A104986 Matrix logarithm of triangle A104980.

Original entry on oeis.org

0, 1, 0, 2, 2, 0, 7, 4, 3, 0, 33, 14, 7, 4, 0, 191, 66, 27, 11, 5, 0, 1297, 382, 137, 48, 16, 6, 0, 10063, 2594, 843, 270, 79, 22, 7, 0, 87669, 20126, 6041, 1820, 495, 122, 29, 8, 0, 847015, 175338, 49219, 14176, 3679, 848, 179, 37, 9, 0, 8989301, 1694030, 448681, 124828, 31361, 6930, 1371, 252, 46, 10, 0
Offset: 0

Views

Author

Paul D. Hanna, Apr 10 2005

Keywords

Comments

Column 0 equals column 1 of triangular matrix A104980, which satisfies: SHIFT_LEFT(column 0 of A104980^p) = p*(column p+1 of A104980) for p>=0. Column 1 equals twice column 0.

Examples

			Triangle begins:
        0;
        1,       0;
        2,       2,      0;
        7,       4,      3,      0;
       33,      14,      7,      4,     0;
      191,      66,     27,     11,     5,    0;
     1297,     382,    137,     48,    16,    6,    0;
    10063,    2594,    843,    270,    79,   22,    7,   0;
    87669,   20126,   6041,   1820,   495,  122,   29,   8,  0;
   847015,  175338,  49219,  14176,  3679,  848,  179,  37,  9,  0;
  8989301, 1694030, 448681, 124828, 31361, 6930, 1371, 252, 46, 10, 0; ...
		

Crossrefs

Cf. A104980, A104981 (column 0), A104987 (row sums).

Programs

  • Mathematica
    nmax = 10;
    M = Table[If[n == k, 0, If[n == k+1, -n+1, -Coefficient[(1-1/Sum[i! x^i, {i, 0, n}])/x + O[x]^n, x, n-k-1]]], {n, 1, nmax+1}, {k, 1, nmax+1}];
    T[n_, k_] /; 0 <= k <= n := Sum[(-1)^p MatrixPower[M, p][[n+1, k+1]]/p, {p, 1, n+1}]; T[, ] = 0;
    Table[T[n, k], {n, 0, nmax}, {k, 0, n}] // Flatten (* Jean-François Alcover, Aug 09 2018, from PARI *)
  • PARI
    T(n,k)=if(n
    				

Formula

T(n, 0) = A104981(n), T(n+1, 1) = 2*T(n, 0) for n>=0.

A383450 2nd diagonal (from right) in A104978.

Original entry on oeis.org

2, 21, 180, 1430, 10920, 81396, 596904, 4326300, 31081050, 221760825, 1573537680, 11114897976, 78215948720, 548652722520, 3838040704080, 26784871943928, 186537501038070, 1296717366119175, 8999440181955300, 62366467037593950, 431633967218324640, 2983755440056831440, 20603495011611002400, 142131208489591604400
Offset: 0

Views

Author

N. J. A. Sloane, May 02 2025

Keywords

Crossrefs

Cf. A104987.

Programs

  • Maple
    From Peter Luschny, May 04 2025: (Start)
    a := n -> (3*n + 4)!/(n!*2*(2 + 2*n + 1)!): seq(a(n), n = 0..23);
    gf := 2*hypergeom([5/3, 7/3], [5/2], (27*x)/4):
    ser := series(gf, x, 25): seq(coeff(ser, x, k), k = 0..23);  (End)

Formula

From Peter Luschny, May 04 2025: (Start)
a(n) = (3*n + 4)! / (2*n!*(3 + 2*n)!).
a(n) = [x^n] 2*hypergeom([5/3, 7/3], [5/2], (27*x)/4). (End)

A383451 3nd diagonal (from right) in A104978.

Original entry on oeis.org

5, 84, 990, 10010, 92820, 813960, 6864396, 56241900, 450675225, 3548173200, 27536909400, 211183061544, 1603426948760, 12070359895440, 90193956545880, 669621798598200, 4943243777508855, 36308086251336900, 265483485367681350, 1933360478165412450, 14028103934595550800, 101447684961932268960, 731424072912190585200, 5258854714114889362800
Offset: 0

Views

Author

N. J. A. Sloane, May 02 2025

Keywords

Crossrefs

Cf. A104987.

Programs

  • Maple
    From Peter Luschny, May 04 2025:  (Start)
    a := n -> (3*n + 6)!/(6*n!*(3 + 2*n + 1)!): seq(a(n), n = 0..23);
    gf := 5*hypergeom([7/3, 8/3], [5/2], (27*x)/4):
    ser := series(gf, x, 25): seq(coeff(ser, x, k), k = 0..23);  (End)

Formula

From Peter Luschny, May 04 2025: (Start)
a(n) = (3*n + 6)!/(6*n!*(3 + 2*n + 1)!).
a(n) = [x^n] 5*hypergeom([7/3, 8/3], [5/2], (27*x)/4). (End)

A383452 Column 3 in A104978.

Original entry on oeis.org

0, 0, 0, 12, 165, 1430, 10010, 61880, 352716, 1899240, 9806280, 49031400, 239028075, 1141710570, 5362579950, 24837212400, 113678010600, 515030986800, 2312957340720, 10307744670600, 45626928615450, 200758485907980, 878623171119540, 3826892034209552, 16596215454480200, 71691488703052400, 308585103547921200, 1323929637802371600
Offset: 0

Views

Author

N. J. A. Sloane, May 02 2025

Keywords

Crossrefs

Cf. A104987.

Programs

  • Maple
    a := n -> ifelse(n < 3, 0, (3 + 2*n)! / (6*(n - 3)!*(n + 4)!)): seq(a(n), n = 0..27);
    y := sqrt(1 - 4*x): gf := (1/(2*(x*y)^4))*((210*x^4 - 420*x^3 + 252*x^2 - 60*x + 5)/y -(32*x^4 - 176*x^3 + 162*x^2 - 50*x + 5)): ser := series(gf, x, 34):
    seq(coeff(ser, x, n), n = 0..27); # Peter Luschny, May 04 2025

Formula

From Peter Luschny, May 04 2025: (Start)
a(n) = (3 + 2*n)! / (6*(n - 3)!*(n + 4)!) for n >= 3.
a(n) = [x^n] (1/(2*(x*y)^4))*((210*x^4 - 420*x^3 + 252*x^2 - 60*x + 5)/y -(32*x^4 - 176*x^3 + 162*x^2 - 50*x + 5)) where y = sqrt(1 - 4*x). (End)
Showing 1-4 of 4 results.