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 1-6 of 6 results.

A174992 a(n) = n! - A000800(n).

Original entry on oeis.org

0, 0, 1, 4, 19, 107, 682, 4915, 39871, 361138, 3621531, 39884367, 478847750, 6226248403, 87174202427, 1307651621142, 20922657286067, 355686620215179, 6402368573492818, 121645066483568099, 2432901775271051559, 51090940513901948778
Offset: 0

Views

Author

Roger L. Bagula, Dec 02 2010

Keywords

Crossrefs

Programs

  • Mathematica
    a = Table[n! - Sum[(
        Eulerian[n - j, j]), {j, 0, Floor[n/2]}], {n, 0, 30}]

Extensions

Definition corrected by Roger L. Bagula, Dec 03 2010

A178118 Antidiagonal sums of the triangle A060187.

Original entry on oeis.org

0, 1, 1, 2, 7, 25, 100, 469, 2481, 14406, 90995, 621553, 4561112, 35736921, 297435521, 2618575194, 24297706927, 236870849417, 2419213831452, 25820011544781, 287327296473585, 3326999636488190, 40011485288491131
Offset: 0

Views

Author

Roger L. Bagula, May 20 2010

Keywords

Comments

This sequence is an analog to the Lucas formula which obtains A000045 as the antidiagonal sums of the Pascal triangle A007318.

References

  • David M. Burton, Elementary number theory, McGraw Hill (2002), page 286

Crossrefs

Programs

  • Mathematica
    p[x_, n_] = (1 - x)^(n + 1)*Sum[(2*k + 1)^n*x^k, {k, 0, Infinity}];
    f[n_, m_] := CoefficientList[FullSimplify[ExpandAll[p[x, n]]], x][[m + 1]]
    a[n_] := Sum[f[n - m - 1, m], {m, 0, Floor[(n - 1)/2]}]
    Table[a[n], {n, 0, 30}]

Formula

a(n) = sum_{m=0.. floor[(n-1)/2]} A060187(n-m-1,m).

Extensions

Exact definition moved to formula - the Assoc. Eds. of the OEIS, Aug 20 2010

A178134 Sum_{m=0..(n-1)/2} A176263(n-m-1, m).

Original entry on oeis.org

0, 1, 1, 2, -3, -2, -32, -81, -311, -810, -2515, -6864, -19944, -55043, -156023, -433522, -1217427, -3391226, -9488456, -26462205, -73933535, -206293134, -576040339, -1607642688, -4488069168, -12526662167, -34967630447
Offset: 0

Views

Author

Roger L. Bagula, May 20 2010

Keywords

Comments

The limiting ratio is (alternating) A222134, 5 times a root of the polynomial 5x^2+x-1 in the denominator of the g.f.

Crossrefs

Programs

  • Maple
    A178134 := proc(n)
        add( A176263(n-m-1,m), m=0..(n-1)/2) ;
    end proc: # R. J. Mathar, May 15 2016
  • Mathematica
    Clear[a, f, a0, t]
    f[0, a_] := 0; f[1, a_] := 1;
    f[n_, a_] := f[n, a] = f[n - 1, a] + a*f[n - 2, a];
    t[n_, m_, a_] := f[m + 1, a] + f[n + 1 - m, a] - f[n + 1, a];
    a = 5;
    a0[n_] := Sum[t[n - m - 1, m, a], {m, 0, Floor[(n - 1)/2]}];
    Table[a0[n], {n, 0, 30}]
  • PARI
    a(n)=([0,1,0,0,0,0,0,0; 0,0,1,0,0,0,0,0; 0,0,0,1,0,0,0,0; 0,0,0,0,1,0,0,0; 0,0,0,0,0,1,0,0; 0,0,0,0,0,0,1,0; 0,0,0,0,0,0,0,1; 25,5,-25,-4,-6,-2,7,1]^n*[0;1;1;2;-3;-2;-32;-81])[1,1] \\ Charles R Greathouse IV, May 15 2016

Formula

G.f. -x*(1-6*x^2-10*x^3-5*x^4+5*x^5) / ( (x-1)*(1+x)*(5*x^2+x-1)*(5*x^4+x^2-1) ). - R. J. Mathar, Nov 05 2012

Extensions

New name from R. J. Mathar, May 15 2016

A174958 a(n)=Sum((A008292(n - j, j) - C(n - j - 1, j))/2, j=0, [(n - 1)/2]).

Original entry on oeis.org

0, 0, 0, 0, 1, 4, 15, 56, 214, 854, 3607, 16172, 76853, 386082, 2044198, 11373124, 66300473, 403939612, 2566116299, 16962629860, 116452790838, 828903740138, 6107712000563, 46521422681724, 365811331693305, 2965957618809246, 24767913121016790, 212803409969904264
Offset: 0

Views

Author

Roger L. Bagula, Dec 02 2010

Keywords

Comments

Sequence A000800 minus the Lucas Fibonacci sum divided by two.

References

  • Burton, David M.,Elementary number theory,McGraw Hill,N.Y.,2002,p 286, problem 23

Crossrefs

Programs

  • Mathematica
    a = Table[Sum[(Eulerian[n -
          j, j] - Binomial[n - j - 1, j])/2, {j, 0,
                Floor[(n - 1)/2]}], {n, 0, 30}]

A174993 a(n) = -Floor[n/2]! + Sum[(Eulerian[n - j, j]), {j, 0, Floor[n/2]}].

Original entry on oeis.org

0, 0, 1, 4, 11, 36, 119, 443, 1718, 7245, 32313, 153730, 771677, 4088053, 22741818, 132596893, 807840501, 5132194862, 33924901021, 232905225561, 1657803862422, 12215420390037, 93042805475305, 731622623516178, 5931914758691917, 49535825763153373, 425606813712984146, 3758735172560999933, 34089943206777076429, 317245175458777517030
Offset: 1

Views

Author

Roger L. Bagula, Dec 02 2010

Keywords

Crossrefs

Cf. A000800.

Programs

  • Mathematica
    <
    				

Formula

a(n)=-Floor[n/2]! + Sum[(Eulerian[n - j, j]), {j, 0, Floor[n/2]}]=A000800(n)-Floor[(n-1)/2]!

A344393 T(n, k) = Eulerian1(n - k, k), for n >= 0 and 0 <= k <= floor(n/2). Triangle read by rows.

Original entry on oeis.org

1, 1, 1, 0, 1, 1, 1, 4, 0, 1, 11, 1, 1, 26, 11, 0, 1, 57, 66, 1, 1, 120, 302, 26, 0, 1, 247, 1191, 302, 1, 1, 502, 4293, 2416, 57, 0, 1, 1013, 14608, 15619, 1191, 1, 1, 2036, 47840, 88234, 15619, 120, 0, 1, 4083, 152637, 455192, 156190, 4293, 1
Offset: 0

Views

Author

Peter Luschny, May 17 2021

Keywords

Comments

The antidiagonal representation of the first order Eulerian numbers (A173018).

Examples

			Triangle starts:
[ 0] [1]
[ 1] [1]
[ 2] [1,    0]
[ 3] [1,    1]
[ 4] [1,    4,     0]
[ 5] [1,   11,     1]
[ 6] [1,   26,    11,     0]
[ 7] [1,   57,    66,     1]
[ 8] [1,  120,   302,    26,    0]
[ 9] [1,  247,  1191,   302,    1]
[10] [1,  502,  4293,  2416,   57, 0]
[11] [1, 1013, 14608, 15619, 1191, 1]
		

Crossrefs

Cf. A000800 (row sums).
Cf. A173018.

Programs

  • Maple
    T := (n, k) -> combinat:-eulerian1(n - k, k):
    seq(print(seq(T(n, k), k=0..n/2)), n = 0..11);
Showing 1-6 of 6 results.