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.

A383150 a(n) = Sum_{k=0..n} k^3 * (-1)^k * 3^(n-k) * binomial(n,k).

Original entry on oeis.org

0, -1, 2, 18, 64, 160, 288, 224, -1024, -6912, -28160, -95744, -294912, -851968, -2351104, -6266880, -16252928, -41222144, -102629376, -251527168, -608174080, -1453326336, -3437232128, -8055160832, -18723373056, -43201331200, -99019128832, -225586446336
Offset: 0

Views

Author

Seiichi Manyama, Apr 18 2025

Keywords

Crossrefs

Programs

  • Magma
    [2^(n-3) * (-12*n+9*n^2-n^3): n in [0..30]]; // Vincenzo Librandi, May 02 2025
  • Mathematica
    Table[2^(n-3)*(-12*n+9*n^2-n^3),{n,0,30}] (* Vincenzo Librandi, May 02 2025 *)
  • PARI
    a(n) = 2^(n-3)*(-12*n+9*n^2-n^3);
    

Formula

a(n) = 2^(n-3) * (-12*n + 9*n^2 - n^3).

A383152 a(n) = Sum_{k=0..n} k^5 * (-1)^k * 3^(n-k) * binomial(n,k).

Original entry on oeis.org

0, -1, 26, 18, -272, -1400, -4032, -7168, -1024, 55296, 294400, 1086976, 3354624, 9132032, 22249472, 47923200, 85983232, 99155968, -102629376, -1237712896, -5688524800, -20775960576, -67868033024, -207022456832, -602167836672, -1690304512000, -4613767954432
Offset: 0

Views

Author

Seiichi Manyama, Apr 18 2025

Keywords

Crossrefs

Programs

  • Magma
    [&+[k^5 * (-1)^k * 3^(n-k) * Binomial(n, k): k in [0..n]]: n in [0..29]]; // Vincenzo Librandi, Apr 23 2025
  • Mathematica
    Table[2^(n-5)*(-480*n+690*n^2-255*n^3+30*n^4-n^5),{n,0,50}] (* Vincenzo Librandi, Apr 24 2025 *)
  • PARI
    a(n) = 2^(n-5)*(-480*n+690*n^2-255*n^3+30*n^4-n^5);
    

Formula

a(n) = 2^(n-5) * (-480*n + 690*n^2 - 255*n^3 + 30*n^4 - n^5).

A383155 a(n) = Sum_{k=0..n} k^6 * (-1)^k * 3^(n-k) * binomial(n,k).

Original entry on oeis.org

0, -1, 58, -180, -1304, -2920, 1008, 34496, 163840, 525312, 1285120, 2241536, 1124352, -12113920, -72052736, -282378240, -924581888, -2699493376, -7201751040, -17666670592, -39507722240, -77918109696, -121883328512, -78622228480, 453588811776, 2904974950400, 11885785120768
Offset: 0

Views

Author

Seiichi Manyama, Apr 18 2025

Keywords

Crossrefs

Programs

  • Magma
    [&+[k^6 * (-1)^k * 3^(n-k) * Binomial(n,k): k in [0..n]]: n in [0..29]]; // Vincenzo Librandi, Apr 23 2025
  • Mathematica
    Table[Sum[(k^6*(-1)^k*3^(n-k))*Binomial[n,k],{k,0,n}],{n,0,30}] (* Vincenzo Librandi, Apr 23 2025 *)
  • PARI
    a(n) = 2^(n-6)*(-4368*n+7290*n^2-3555*n^3+645*n^4-45*n^5+n^6);
    

Formula

a(n) = 2^(n-6) * (-4368*n + 7290*n^2 - 3555*n^3 + 645*n^4 - 45*n^5 + n^6).

A383149 Triangle T(n,k), n >= 0, 0 <= k <= n, read by rows, where T(n,k) = (-1)^k * [m^k] (1/2^(m-n)) * Sum_{k=0..m} k^n * (-1)^m * 3^(m-k) * binomial(m,k).

Original entry on oeis.org

1, 0, 1, 0, 3, 1, 0, 12, 9, 1, 0, 66, 75, 18, 1, 0, 480, 690, 255, 30, 1, 0, 4368, 7290, 3555, 645, 45, 1, 0, 47712, 88536, 52290, 12705, 1365, 63, 1, 0, 608016, 1223628, 831684, 249585, 36120, 2562, 84, 1, 0, 8855040, 19019664, 14405580, 5073012, 915705, 87696, 4410, 108, 1
Offset: 0

Views

Author

Seiichi Manyama, Apr 18 2025

Keywords

Examples

			f_0(m) = 1.
f_1(m) =      -m.
f_2(m) =    -3*m +     m^2.
f_3(m) =   -12*m +   9*m^2 -     m^3.
f_4(m) =   -66*m +  75*m^2 -  18*m^3 +    m^4.
f_5(m) =  -480*m + 690*m^2 - 255*m^3 + 30*m^4 - m^5.
Triangle begins:
  1;
  0,     1;
  0,     3,     1;
  0,    12,     9,     1;
  0,    66,    75,    18,     1;
  0,   480,   690,   255,    30,    1;
  0,  4368,  7290,  3555,   645,   45,  1;
  0, 47712, 88536, 52290, 12705, 1365, 63, 1;
  ...
		

Crossrefs

Columns k=0..3 give A000007, A123227(n-1), A383163, A383164.
Row sums give A122704.

Programs

  • PARI
    T(n, k) = sum(j=k, n, 2^(n-j)*stirling(n, j, 2)*abs(stirling(j, k, 1)));
    
  • Sage
    def a_row(n):
        s = sum(2^(n-k)*stirling_number2(n, k)*rising_factorial(x, k) for k in (0..n))
        return expand(s).list()
    for n in (0..9): print(a_row(n))

Formula

f_n(m) = (1/2^(m-n)) * Sum_{k=0..m} k^n * (-1)^m * 3^(m-k) * binomial(m,k).
T(n,k) = [m^k] f_n(-m).
T(n,k) = Sum_{j=k..n} 2^(n-j) * Stirling2(n,j) * |Stirling1(j,k)|.
T(n,k) = [x^k] Sum_{k=0..n} 2^(n-k) * Stirling2(n,k) * RisingFactorial(x,k).
Sum_{k=0..n} (-1)^k * T(n,k) = f_m(1) = -2^(n-1) for n > 0.
E.g.f. of column k (with leading zeros): g(x)^k / k! with g(x) = -log(1 - (exp(2*x) - 1)/2).
Showing 1-4 of 4 results.