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.

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A331329 a(n) = binomial(5*n, n)*hypergeom([-4*n, -n], [-5*n], -1).

Original entry on oeis.org

1, 9, 145, 2625, 50049, 982729, 19665841, 398796225, 8166636545, 168502295625, 3497529199185, 72949645000065, 1527671538372225, 32100078290806665, 676451066002195825, 14290577765009652865, 302557549412667613185, 6417968867896642617225, 136371773642235542394385
Offset: 0

Views

Author

Peter Luschny, Jan 31 2020

Keywords

Comments

Special case of generalized Delannoy numbers (see cross-references):
T(n, k) = binomial(k*n, n)*hypergeom([(1-k)*n, -n], [-k*n], -1).

Crossrefs

Cf. A001850 (k=2), A026000 (k=3), A026001 (k=4), this sequence (k=5), A341491 (k=6).

Programs

  • Mathematica
    a[n_] := Binomial[5 n, n] Hypergeometric2F1[-4 n, -n, -5 n, -1];
    Array[a, 19, 0]

Formula

a(n) ~ sqrt(5 + 21/sqrt(17)) * (349 + 85*sqrt(17))^n / (sqrt(Pi*n) * 2^(5*n + 2)). - Vaclav Kotesovec, Feb 13 2021

A008419 Crystal ball sequence for 9-dimensional cubic lattice.

Original entry on oeis.org

1, 19, 181, 1159, 5641, 22363, 75517, 224143, 598417, 1462563, 3317445, 7059735, 14218905, 27298155, 50250765, 89129247, 152951073, 254831667, 413442773, 654862247, 1014889769, 1541911931, 2300409629, 3375210671, 4876601009, 6946419011, 9765268709
Offset: 0

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Author

Keywords

Comments

This is row/column 9 of the Delannoy numbers array, A008288, which is the main entry for these numbers, listing many more properties. - Shel Kaphan, Jan 07 2023

Crossrefs

Cf. A240876.
Row/column 9 of A008288.

Programs

  • Mathematica
    CoefficientList[Series[(z + 1)^9/(z - 1)^10, {z, 0, 200}], z] (* Vladimir Joseph Stephan Orlovsky, Jun 19 2011 *)
    LinearRecurrence[{10,-45,120,-210,252,-210,120,-45,10,-1},{1,19,181,1159,5641,22363,75517,224143,598417,1462563},40] (* Harvey P. Dale, Jul 25 2013 *)

Formula

G.f.: (1+x)^9/(1-x)^10.
a(n) = (4*n^9+18*n^8+240*n^7+756*n^6+3612*n^5+7182*n^4+14360*n^3+14724*n^2+ 10134*n+2835)/2835. - Johannes W. Meijer, Jul 14 2013
a(0)=1, a(1)=19, a(2)=181, a(3)=1159, a(4)=5641, a(5)=22363, a(6)=75517, a(7)=224143, a(8)=598417, a(9)=1462563, a(n)=10*a(n-1)-45*a(n-2)+ 120*a(n-3)- 210*a(n-4)+252*a(n-5)-210*a(n-6)+120*a(n-7)-45*a(n-8)+ 10*a(n-9)- a(n-10). - Harvey P. Dale, Jul 25 2013
Sum_{n >= 1} (-1)^(n+1)/(n*a(n-1)*a(n)) = (1 - 1/2 + 1/3 - ... + 1/9) - log(2). - Peter Bala, Mar 23 2024

A047666 Square array a(n,k) read by antidiagonals: a(n,1)=n, a(1,k)=k, a(n,k) = a(n-1,k-1) + a(n-1,k) + a(n,k-1).

Original entry on oeis.org

1, 2, 2, 3, 5, 3, 4, 10, 10, 4, 5, 17, 25, 17, 5, 6, 26, 52, 52, 26, 6, 7, 37, 95, 129, 95, 37, 7, 8, 50, 158, 276, 276, 158, 50, 8, 9, 65, 245, 529, 681, 529, 245, 65, 9, 10, 82, 360, 932, 1486, 1486, 932, 360, 82, 10, 11, 101, 507, 1537, 2947, 3653
Offset: 1

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Author

Keywords

Crossrefs

Main diagonal is A002002. Rows give A002522, A047667, A047668, ...

Programs

  • Maple
    A047666 := proc(n,k) option remember; if n = 1 then k; elif k = 1 then n; else A047666(n-1,k-1)+A047666(n,k-1)+A047666(n-1,k); fi; end;
  • Mathematica
    nmax = 11; a[1, k_] := k; a[n_, 1] := n; a[n_, k_] := a[n, k] = a[n-1, k-1] + a[n, k-1] + a[n-1, k]; Flatten[ Table[ a[n-k+1, k], {n, 1, nmax}, {k, 1, n}]] (* Jean-François Alcover, Feb 10 2012 *)

Formula

T(n, m) = (Sum_{i=1..n-m}(2*i+1)*U(n-i-1, m-1)) + (Sum_{i=1..m} (2*i+1)*U(n-2, m-i)) - U(n-2, m-1) where U(n, m) = A008288(n, m). - Floor van Lamoen, Aug 16 2001

A047671 Square array a(n,k) read by antidiagonals: a(n,1)=1, a(1,k)=1, a(n,k) = 1 + a(n-1,k-1) + a(n-1,k) + a(n,k-1).

Original entry on oeis.org

1, 1, 1, 1, 4, 1, 1, 7, 7, 1, 1, 10, 19, 10, 1, 1, 13, 37, 37, 13, 1, 1, 16, 61, 94, 61, 16, 1, 1, 19, 91, 193, 193, 91, 19, 1, 1, 22, 127, 346, 481, 346, 127, 22, 1, 1, 25, 169, 565, 1021, 1021, 565, 169, 25, 1, 1, 28, 217, 862, 1933, 2524, 1933, 862
Offset: 1

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Author

Keywords

Crossrefs

Main diagonal is A027618. Rows give A003215, A047672, A047673, A047674.
a(n, k) = A008288(n-1, k-1) + A047662(n-1, k-1).

Programs

  • Maple
    A047671 := proc(n,k) option remember; if n = 1 then 1; elif k = 1 then 1; else 1+A047671(n-1,k-1)+A047671(n,k-1)+A047671(n-1,k); fi; end;
  • Mathematica
    nmax = 12; a[, 1] = 1; a[1, ] = 1; a[n_ /; n > 1, k_ /; k > 1] :=  a[n, k] = 1 + a[n-1, k-1] + a[n-1, k] + a[n, k-1]; Flatten[ Table[ a[n-k , k], {n, 1, nmax}, {k, 1, n-1}]] (* Jean-François Alcover, Jul 19 2012 *)

Extensions

Description corrected by Henry Bottomley, May 09 2000

A103136 Inverse of the Delannoy triangle.

Original entry on oeis.org

1, -1, 1, 2, -3, 1, -6, 10, -5, 1, 22, -38, 22, -7, 1, -90, 158, -98, 38, -9, 1, 394, -698, 450, -194, 58, -11, 1, -1806, 3218, -2126, 978, -334, 82, -13, 1, 8558, -15310, 10286, -4942, 1838, -526, 110, -15, 1, -41586, 74614, -50746, 25150, -9922, 3142, -778, 142, -17, 1, 206098, -370610, 254410, -129050
Offset: 0

Views

Author

Paul Barry, Jan 24 2005

Keywords

Comments

The Delannoy triangle is A008288 viewed as a number triangle. It is then given by the Riordan array (1/(1-x), x(1+x)/(1-x)). The absolute value of A103136 is the Riordan array (1+xS(x),xS(x)) which is the inverse of the signed Delannoy triangle (1/(1+x), x(1-x)/(1+x)).
Triangle T(n,k), 0 <= k <= n, read by rows, given by [ -1, -1, -2, -1, -2, -1, -2, -1, -2, ... ] DELTA [ 1, 0, 0, 0, 0, 0, 0, 0, ... ] where DELTA is the operator defined in A084938; the unsigned version is given by [ 1, 1, 2, 1, 2, 1, 2, 1, 2, ...] DELTA [ 1, 0, 0, 0, 0, 0, 0, 0, ... ]. - Philippe Deléham, Jul 08 2005
The unsigned number |T(n,k)| counts Schroeder n-paths whose ascent starting at the initial vertex has length k. A Schroeder n-path is a lattice path starting from (0,0), ending at (2n,0), consisting only of steps U=(1,1) (upsteps), D=(1,-1) (downsteps) and F=(2,0) (flatsteps) and never going below the x-axis. For example, |T(2,0)| = 2 counts FF, FUD; |T(2,1)| = 3 counts UFD, UDF, UDUD; |T(2,2)| = 1 counts UUDD. - David Callan, Jul 14 2006

Examples

			From _Paul Barry_, Apr 29 2009: (Start)
Triangle begins
    1;
   -1,    1;
    2,   -3,    1;
   -6,   10,   -5,    1;
   22,  -38,   22,   -7,    1;
  -90,  158,  -98,   38,   -9,    1;
  394, -698,  450, -194,   58,  -11,    1;
Production matrix is
  -1,  1,
   1, -2,  1,
  -1,  2, -2,  1,
   1, -2,  2, -2,  1,
  -1,  2, -2,  2, -2,  1
The unsigned triangle has production matrix
  1, 1,
  1, 2, 1,
  1, 2, 2, 1,
  1, 2, 2, 2, 1,
  1, 2, 2, 2, 2, 1 (End)
		

Programs

  • SageMath
    def A103136(dim): # Returns a triangle with 'dim' rows
        M = matrix([[simplify(hypergeometric([-n, n-k], [1], 2))
              for n in range(k+1)] + [0]*(dim-k-1) for k in range(dim)])
        return [row[:n+1] for n, row in enumerate(M.inverse())]
    A103136(9)  # Peter Luschny, Nov 16 2023

Formula

Riordan array (1-f(x), f(x)) with f(x) = xS(-x), S(x) the g.f. of the large Schroeder numbers A006318. Equivalent to Riordan array (g(x), 1-g(x)) where g(x) = (3+x-sqrt(1+6x+x^2))/2.
G.f.: 1/(1 + (x - xy)/(1 + x/(1 + 2x/(1 + x/(1 + 2x/(1+... (continued fraction). - Paul Barry, Apr 29 2009

A128966 Triangle read by rows of coefficients of polynomials P[n](x) defined by P[0]=0, P[1]=x+1; for n >= 2, P[n]=(x+1)*P[n-1]+x*P[n-2].

Original entry on oeis.org

0, 1, 1, 1, 2, 1, 1, 4, 4, 1, 1, 6, 10, 6, 1, 1, 8, 20, 20, 8, 1, 1, 10, 34, 50, 34, 10, 1, 1, 12, 52, 104, 104, 52, 12, 1, 1, 14, 74, 190, 258, 190, 74, 14, 1, 1, 16, 100, 316, 552, 552, 316, 100, 16, 1, 1, 18, 130, 490, 1058, 1362, 1058, 490, 130, 18, 1, 1, 20, 164
Offset: 0

Views

Author

N. J. A. Sloane, May 10 2007

Keywords

Comments

A variant of A008288 (they satisfy the same recurrence).

Examples

			Triangle begins:
0
1, 1
1, 2, 1
1, 4, 4, 1
1, 6, 10, 6, 1
1, 8, 20, 20, 8, 1
1, 10, 34, 50, 34, 10, 1
1, 12, 52, 104, 104, 52, 12, 1
1, 14, 74, 190, 258, 190, 74, 14, 1
1, 16, 100, 316, 552, 552, 316, 100, 16, 1
		

Crossrefs

Cf. A163271 (row sums), A110170 (central terms).
Cf. A102413.

Programs

  • Haskell
    a128966 n k = a128966_tabl !! n !! k
    a128966_row n = a128966_tabl !! n
    a128966_tabl = map fst $ iterate
       (\(us, vs) -> (vs, zipWith (+) ([0] ++ us ++ [0]) $
                          zipWith (+) ([0] ++ vs) (vs ++ [0]))) ([0], [1, 1])
    -- Reinhard Zumkeller, Jul 20 2013
  • Maple
    P[0]:=0;
    P[1]:=x+1;
    for n from 2 to 14 do
    P[n]:=expand((x+1)*P[n-1]+x*P[n-2]);
    lprint(P[n]);
    lprint(seriestolist(series(P[n],x,200)));
    od:
  • Mathematica
    t[n_, k_] := 2^(1-n)*Binomial[n, k]*Sum[Binomial[n, 2*m+1]*HypergeometricPFQ[{-k, -m, k-n}, {1/2-n/2, -n/2}, -1], {m, 0, (n-1)/2}]; Table[t[n, k], {n, 0, 11}, {k, 0, n}] // Flatten (* Jean-François Alcover, Jan 09 2014, after Max Alekseyev *)
  • PARI
    { T(n,k) = sum(m=0,(n-1)\2, binomial(n,2*m+1) * sum(j=0,m, binomial(m,j) * binomial(n-2*j,k-j) * 2^(2*j+1-n) ) ) } \\ Max Alekseyev, Mar 10 2008
    

Formula

P[n](x) = (x+1) * ( ((x+1+sqrt(x^2+6x+1))/2)^n - ((x+1-sqrt(x^2+6x+1))/2)^n ) / sqrt(x^2+6x+1) - Max Alekseyev, Mar 10 2008
P[n](x) = (x+1) * (sqrt(x)*I)^(n-1) * U[n-1](-I*(x+1)/sqrt(x)/2), where U[n](t) is Chebyshev polynomial of the 2nd kind. - Max Alekseyev, Mar 10 2008

A143411 Square array, read by antidiagonals: form the Euler-Seidel matrix for the sequence {2^k*k!} and then divide column k by 2^k*k!.

Original entry on oeis.org

1, 3, 1, 13, 5, 1, 79, 33, 7, 1, 633, 277, 61, 9, 1, 6331, 2849, 643, 97, 11, 1, 75973, 34821, 7993, 1225, 141, 13, 1, 1063623, 493825, 114751, 17793, 2071, 193, 15, 1, 17017969, 7977173, 1870837, 292681, 34361, 3229, 253, 17, 1
Offset: 0

Views

Author

Peter Bala, Aug 19 2008

Keywords

Comments

This table is closely connected to the constant 1/sqrt(e). The row, column and diagonal entries of this table occur in series acceleration formulas for 1/sqrt(e). For a similar table based on the differences of the sequence {2^k*k!} and related to the constant sqrt(e), see A143410. For other arrays similarly related to constants see A086764 (for e), A143409 (for 1/e), A008288 (for log(2)), A108625 (for zeta(2)) and A143007 (for zeta(3)).

Examples

			The Euler-Seidel matrix for the sequence {2^k*k!} begins
  ========================================
  n\k|     0     1     2     3     4     5
  ========================================
  0  |     1     2     8    48   384  3840
  1  |     3    10    56   432  4224
  2  |    13    66   488  4656
  3  |    79   554  5144
  4  |   633  5698
  5  |  6331
  ...
.
  Dividing the k-th column by 2^k*k! gives
  ========================================
  n\k|     0     1     2     3     4     5
  ========================================
  0  |     1     1     1     1     1     1
  1  |     3     5     7     9    11
  2  |    13    33    61    97
  3  |    79   277   643
  4  |   633  2849
  5  |  6331
  ...
		

Crossrefs

Programs

  • Magma
    A:= func< n,k | (&+[Binomial(n,j)*Factorial(k+j)*2^j/Factorial(k): j in [0..n]]) >; // Array
    A143411:= func< n,k | A(n-k,k) >; // antidiagonal triangle
    [A143411(n,k): k in [0..n], n in [0..12]]; // G. C. Greubel, Oct 05 2023
    
  • Maple
    with combinat: T := (n, k) -> 1/k!*add(2^j*binomial(n,j)*(k+j)!, j = 0..n): for n from 0 to 9 do seq(T(n, k), k = 0..9) end do;
  • Mathematica
    A[n_, k_]:= (1/k!)*Sum[Binomial[n,j]*(k+j)!*2^j, {j,0,n}]; (* array *)
    A143411[n_, k_]:= A[n-k,k]; (* antidiagonals *)
    Table[A143411[n,k], {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Oct 05 2023 *)
  • SageMath
    def A(n,k): return sum(binomial(n,j)*factorial(j+k)*2^j/factorial(k) for j in range(n+1)) # array
    def A143411(n,k): return A(n-k,k) # antidiagonal triangle
    flatten([[A143411(n,k) for k in range(n+1)] for n in range(13)]) # G. C. Greubel, Oct 05 2023

Formula

T(n,k) = (1/k!)*Sum_{j = 0..n} 2^j*binomial(n,j)*(k+j)!.
Relation with Poisson-Charlier polynomials c_n(x,a):
T(n,k) = (-1)^n*c_n(-(k+1),1/2).
Recurrence relations:
T(n,k) = 2*n*T(n-1,k) + T(n,k-1);
T(n,k) = 2*(n+k)*T(n-1,k) + T(n-1,k-1);
T(n,k) = 2*(k+1)*T(n-1,k+1) + T(n-1,k).
Recurrence for row n entries: 2*k*T(n,k) = (2*n+2*k-1)*T(n,k-1) + T(n,k-2).
E.g.f. for column k: exp(y)/(1 - 2*y)^(k+1).
E.g.f. for array: exp(y)/(1 - x - 2*y) = (1 + x + x^2 + ...) + (3 + 5*x + 7*x^2 + ...)*y + (13 + 37*x + 61*x^2 + ...)*y^2/2! + ... .
Series acceleration formulas for 1/sqrt(e):
Row n: 1/sqrt(e) = 2^n*n!*(1/T(n,0) - 1/(2*1!*T(n,0)*T(n,1)) + 1/(2^2*2!*T(n,1)*T(n,2)) - 1/(2^3*3!*T(n,2)*T(n,3)) + ...). For example, row 3 gives 1/sqrt(e) = 48*(1/79 - 1/(2*79*277) + 1/(8*277*643) - 1/(48*643*1225) + ...).
Column k: 1/sqrt(e) = (1 - (1/2)/1! + (1/2)^2/2! - ... + (-1/2)^k/k!) + (-1)^(k+1)/(2^k*k!)*( Sum_{n = 0..inf} 2^n*n!/(T(n,k)*T(n+1,k)) ). For example, column 3 gives 1/sqrt(e) = 29/48 + 1/48*( 1/(1*9) + 2/(9*97) + 8/(97*1225) + 48/(1225*17793) + ... ).
Main diagonal: 1/sqrt(e) = 1 - 2*( 1/(1*5) - 1/(5*61) + 1/(61*1225) - ... ). See A065919.

A180668 a(n) = a(n-1)+a(n-2)+a(n-3)+4*n-8 with a(0)=0, a(1)=0 and a(2)=1.

Original entry on oeis.org

0, 0, 1, 5, 14, 32, 67, 133, 256, 484, 905, 1681, 3110, 5740, 10579, 19481, 35856, 65976, 121377, 223277, 410702, 755432, 1389491, 2555709, 4700720, 8646012, 15902537, 29249369, 53798022, 98950036, 181997539, 334745713
Offset: 0

Views

Author

Johannes W. Meijer, Sep 21 2010

Keywords

Comments

The a(n+2) represent the Kn13 and Kn23 sums of the square array of Delannoy numbers A008288. See A180662 for the definition of these knight and other chess sums.

Crossrefs

Cf. A000073 (Kn11 & Kn21), A089068 (Kn12 & Kn22), A180668 (Kn13 & Kn23), A180669 (Kn14 & Kn24), A180670 (Kn15 & Kn25).

Programs

  • Maple
    nmax:=31: a(0):=0: a(1):=0: a(2):=1: for n from 3 to nmax do a(n):= a(n-1)+a(n-2)+a(n-3)+4*n-8 od: seq(a(n),n=0..nmax);
  • Mathematica
    LinearRecurrence[{3,-2,0,-1,1},{0,0,1,5,14},40] (* Harvey P. Dale, Dec 15 2023 *)

Formula

a(n) = a(n-1)+a(n-2)+a(n-3)+4*n-8 with a(0)=0, a(1)=0 and a(2)=1.
a(n) = a(n-1)+A001590(n+3)-2 with a(0)=0.
a(n) = sum(A008574(m)*A000073(n-m),m=0..n).
a(n+2) = add(A008288(n-k+2,k+2),k=0..floor(n/2)).
GF(x) = (x^2*(1+x)^2)/((1-x)^2*(1-x-x^2-x^3)).
Contribution from Bruno Berselli, Sep 23 2010: (Start)
a(n) = 2*a(n-1)-a(n-4)+4 for n>4.
a(n)-3*a(n-1)+2a(n-2)+a(n-4)-a(n-5) = 0 for n>4. (End)

A180669 a(n) = a(n-1)+a(n-2)+a(n-3)+4*n^2-16*n+18 with a(0)=0, a(1)=0 and a(2)=1.

Original entry on oeis.org

0, 0, 1, 7, 26, 72, 171, 371, 760, 1500, 2889, 5475, 10266, 19116, 35435, 65495, 120832, 222664, 410017, 754671, 1388650, 2554784, 4699707, 8644907, 15901336, 29248068, 53796617, 98948523, 181995914, 334743972, 615691547
Offset: 0

Views

Author

Johannes W. Meijer, Sep 21 2010

Keywords

Comments

The a(n+2) represent the Kn14 and Kn24 sums of the square array of Delannoy numbers A008288. See A180662 for the definition of these knight and other chess sums.

Crossrefs

Cf. A000073 (Kn11 & Kn21), A089068 (Kn12 & Kn22), A180668 (Kn13 & Kn23), A180669 (Kn14 & Kn24), A180670 (Kn15 & Kn25).

Programs

  • Maple
    nmax:=30: a(0):=0: a(1):=0: a(2):=1: for n from 3 to nmax do a(n):= a(n-1)+a(n-2)+a(n-3)+4*(n-2)^2+2 od: seq(a(n),n=0..nmax);
  • Mathematica
    nxt[{n_,a_,b_,c_}]:={n+1,b,c,a+b+c+4n(n-2)+6}; NestList[nxt,{2,0,0,1},30][[;;,2]] (* or *) LinearRecurrence[{4,-5,2,-1,2,-1},{0,0,1,7,26,72},40] (* Harvey P. Dale, Jul 13 2024 *)

Formula

a(n) = a(n-1)+a(n-2)+a(n-3)+4*(n-2)^2+2 with a(0)=0, a(1)=0 and a(2)=1.
a(n) = a(n-1)+A001590(n+5)-2-4*n with a(0)=0.
a(n) = Sum_{m=0..n} A005899(m)*A000073(n-m).
a(n+2) = Sum_{k=0..floor(n/2)} A008288(n-k+3,k+3).
GF(x) = (x^2*(1+x)^3)/((1-x)^3*(1-x-x^2-x^3)).
From Bruno Berselli, Sep 23 2010: (Start)
a(n) = 3*a(n-1)-2a(n-2)-a(n-4)+a(n-5)+8 for n>4.
a(n)-4*a(n-1)+5a(n-2)-2*a(n-3)+a(n-4)-2*a(n-5)+a(n-6) = 0 for n>5. (End)

A180670 a(n) = a(n-1)+a(n-2)+a(n-3)+(8*n^3-48*n^2+112*n-96)/3 with a(0)=0, a(1)=0 and a(2)=1.

Original entry on oeis.org

0, 0, 1, 9, 42, 140, 383, 925, 2056, 4316, 8705, 17069, 32810, 62192, 116743, 217673, 404000, 747496, 1380177, 2544865, 4688186, 8631620, 15886111, 29230725, 53776968, 98926372, 181971057, 334716197, 615660634, 1132400520
Offset: 0

Views

Author

Johannes W. Meijer, Sep 21 2010

Keywords

Comments

The a(n+2) represent the Kn15 and Kn25 sums of the square array of Delannoy numbers A008288. See A180662 for the definition of these knight and other chess sums.

Crossrefs

Cf. A000073 (Kn11 & Kn21), A089068 (Kn12 & Kn22), A180668 (Kn13 & Kn23), A180669 (Kn14 & Kn24), A180670 (Kn15 & Kn25).

Programs

  • Maple
    nmax:=29: a(0):=0: a(1):=0: a(2):=1: for n from 3 to nmax do a(n):= a(n-1)+a(n-2)+a(n-3)+(8*n^3-48*n^2+112*n-96)/3 od: seq(a(n),n=0..nmax);
  • Mathematica
    RecurrenceTable[{a[0]==a[1]==0,a[2]==1,a[n]==a[n-1]+a[n-2]+a[n-3]+(8n^3-48n^2+112n-96)/3},a,{n,30}] (* or *) LinearRecurrence[{5,-9,7,-3,3,-3,1},{0,0,1,9,42,140,383},30] (* Harvey P. Dale, Dec 04 2019 *)

Formula

a(n) = a(n-1)+a(n-2)+a(n-3)+(8*n^3-48*n^2+112*n-96)/3 with a(0)=0, a(1)=0 and a(2)=1.
a(n) = a(n-1)+A001590(n+7)-(12+4*n+4*n^2) with a(0)=0.
a(n) = sum(A008412(m)*A000073(n-m),m=0..n).
a(n+2) = add(A008288(n-k+4,k+4),k=0..floor(n/2)).
GF(x) = (x^2*(1+x)^4)/((1-x)^4*(1-x-x^2-x^3)).
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