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 1-7 of 7 results.

A127276 Hankel transform of A127275.

Original entry on oeis.org

1, 1, -2, -16, -64, -208, -608, -1664, -4352, -11008, -27136, -65536, -155648, -364544, -843776, -1933312, -4390912, -9895936, -22151168, -49283072, -109051904, -240123904, -526385152, -1149239296, -2499805184, -5419040768
Offset: 0

Views

Author

Paul Barry, Jan 10 2007

Keywords

Comments

The inverse binomial transform of this sequence yields 1, 0, -3, -8,..., which is 1 followed by the negated terms of A005563. [Paul Curtz, Dec 07 2010]
The smallest odd prime divisor of a(n) is >= 13. - Vladimir Shevelev, Feb 03 2014

Crossrefs

Programs

Formula

Conjecture: G.f.: -(4*x-1)*(x-1) / ( (2*x-1)^3 ) and a(n) = 2^n-n*(n+1)*2^(n-2). - R. J. Mathar, Dec 11 2010
a(n) = A178987(n) - A178987(n+1). - Klaus Brockhaus, Jan 08 2011

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).

A383151 a(n) = Sum_{k=0..n} k^4 * (-1)^k * 3^(n-k) * binomial(n,k).

Original entry on oeis.org

0, -1, 10, 36, 40, -160, -1152, -4480, -13568, -34560, -74240, -123904, -92160, 425984, 2867200, 11796480, 40763392, 128122880, 378667008, 1070858240, 2928148480, 7795113984, 20300431360, 51900317696, 130610626560, 324219699200, 795206483968, 1929715384320
Offset: 0

Views

Author

Seiichi Manyama, Apr 18 2025

Keywords

Crossrefs

Programs

  • Magma
    [&+[k^4 * (-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^4*(-1)^k*3^(n-k))*Binomial[n,k],{k,0,n}],{n,0,30}] (* Vincenzo Librandi, Apr 23 2025 *)
  • PARI
    a(n) = 2^(n-4)*(-66*n+75*n^2-18*n^3+n^4);
    

Formula

a(n) = 2^(n-4) * (-66*n + 75*n^2 - 18*n^3 + n^4).

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).

A181407 a(n) = (n-4)*(n-3)*2^(n-2).

Original entry on oeis.org

3, 3, 2, 0, 0, 16, 96, 384, 1280, 3840, 10752, 28672, 73728, 184320, 450560, 1081344, 2555904, 5963776, 13762560, 31457280, 71303168, 160432128, 358612992, 796917760, 1761607680, 3875536896, 8489271296, 18522046464, 40265318400, 87241523200, 188441690112
Offset: 0

Views

Author

Paul Curtz, Jan 28 2011

Keywords

Comments

Binomial transform of (3, 0, -1, followed by A005563).
The sequence and its successive differences are:
3, 3, 2, 0, 0, 16, 96, 384, a(n),
0, -1, -2, 0, 16, 80, 288, 896, A178987,
-1, -1, 2, 16, 64, 208, 608, 2688, -A127276,
0, 3, 14, 48, 144, 400, 1056, 2688, A176027,
3, 11, 34, 96, 256, 656, 1632, 3968, A084266(n+1)
8, 23, 62, 160, 400, 976, 2336, 5504,
15, 39, 98, 240, 576, 1360, 3168, 7296.
Division of the k-th column by abs(A174882(k)) gives
3, 3, 1, 0, 0, 1, 3, 3, 5, 15, 21, 14, A064038(n-3),
0, -1, -1, 0, 1, 5, 9, 7, 10, 27, 35, 22, A160050(n-3),
-1, -1, 1, 2, 4, 13, 19, 13, 17, 43, 53, 32, A176126,
0, 3, 7, 6, 9, 25, 33, 21, 26, 63, 75, 44, A178242,
3, 11, 17, 12, 16, 41, 51, 31, 37, 87, 101, 58,
8 23, 31, 20, 25, 61, 73, 43, 50, 115, 131, 74,
15, 39, 49, 30, 36, 85, 99, 57, 65, 147, 165, 92.

Crossrefs

Programs

  • GAP
    List([0..40], n-> (n-4)*(n-3)*2^(n-2)); # G. C. Greubel, Feb 21 2019
  • Magma
    [(n-4)*(n-3)*2^(n-2): n in [0..40] ]; // Vincenzo Librandi, Feb 01 2011
    
  • Mathematica
    Table[(n-4)*(n-3)*2^(n-2), {n,0,40}] (* G. C. Greubel, Feb 21 2019 *)
  • PARI
    vector(40, n, n--; (n-4)*(n-3)*2^(n-2)) \\ G. C. Greubel, Feb 21 2019
    
  • Sage
    [(n-4)*(n-3)*2^(n-2) for n in (0..40)] # G. C. Greubel, Feb 21 2019
    

Formula

a(n) = 16*A001788(n-4).
a(n+1) - a(n) = A178987(n).
G.f.: (3 - 15*x + 20*x^2) / (1-2*x)^3. - R. J. Mathar, Jan 30 2011
E.g.f.: (x^2 - 3*x + 3)*exp(2*x). - G. C. Greubel, Feb 21 2019

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 1-7 of 7 results.