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.

A356777 G.f.: Sum_{n=-oo..+oo} x^(n^2) * C(x)^(2*n-1), where C(x) = 1 + x*C(x)^2 is a g.f. of the Catalan numbers (A000108).

Original entry on oeis.org

1, 1, -3, 0, 1, -5, 5, 0, 0, 1, -7, 14, -7, 0, 0, 0, 1, -9, 27, -30, 9, 0, 0, 0, 0, 1, -11, 44, -77, 55, -11, 0, 0, 0, 0, 0, 1, -13, 65, -156, 182, -91, 13, 0, 0, 0, 0, 0, 0, 1, -15, 90, -275, 450, -378, 140, -15, 0, 0, 0, 0, 0, 0, 0, 1, -17, 119, -442, 935, -1122, 714, -204, 17, 0, 0, 0, 0, 0, 0, 0, 0, 1, -19, 152, -665, 1729, -2717, 2508, -1254, 285, -19
Offset: 0

Views

Author

Paul D. Hanna, Sep 08 2022

Keywords

Examples

			G.f.: A(x) = 1 + x - 3*x^2 + x^4 - 5*x^5 + 5*x^6 + x^9 - 7*x^10 + 14*x^11 - 7*x^12 + x^16 - 9*x^17 + 27*x^18 - 30*x^19 + 9*x^20 + x^25 - 11*x^26 + 44*x^27 - 77*x^28 + 55*x^29 - 11*x^30 + x^36 - 13*x^37 + 65*x^38 - 156*x^39 + 182*x^40 - 91*x^41 + 13*x^42 + x^49 - 15*x^50 + 90*x^51 - 275*x^52 + 450*x^53 - 378*x^54 + 140*x^55 - 15*x^56 + ...
such that
A(x) = ... + x^16/C(x)^9 + x^9/C(x)^7 + x^4/C(x)^5 + x/C(x)^3 + 1/C(x) + x*C(x) + x^4*C(x)^3 + x^9*C(x)^5 + x^16*C(x)^7 + x^25*C(x)^9 + ... + x^(n^2)*C^(2*n-1) + ...
where the Catalan function C(x) = (1 - sqrt(1-4*x))/(2*x) begins
C(x) = 1 + x + 2*x^2 + 5*x^3 + 14*x^4 + 42*x^5 + 132*x^6 + 429*x^7 + 1430*x^8 + 4862*x^9 + ... + A000108(n)*x^n + ...
RELATED TABLE.
This sequence may be written in the form of an irregular triangle:
1,
1, -3, 0,
1, -5, 5, 0, 0,
1, -7, 14, -7, 0, 0, 0,
1, -9, 27, -30, 9, 0, 0, 0, 0,
1, -11, 44, -77, 55, -11, 0, 0, 0, 0, 0,
1, -13, 65, -156, 182, -91, 13, 0, 0, 0, 0, 0, 0,
1, -15, 90, -275, 450, -378, 140, -15, 0, 0, 0, 0, 0, 0, 0,
1, -17, 119, -442, 935, -1122, 714, -204, 17, 0, 0, 0, 0, 0, 0, 0, 0,
1, -19, 152, -665, 1729, -2717, 2508, -1254, 285, -19, 0, 0, 0, 0, 0, 0, 0, 0, 0,
...
Compare the above construction to triangle A082985.

Links

Crossrefs

Cf. A355341, A355342, A355345, A356778, A082985, A000108.

Programs

  • PARI
    /* By Definition: */
{a(n) = my(A, C = 1/x*serreverse(x-x^2 +O(x^(n+2))), M=ceil(sqrt(n+1)));
A = sum(m=-M, M, x^(m^2) * C^(2*m-1) ); polcoeff(A, n)}
for(n=0, 90, print1(a(n), ", "))
  • PARI
    /* Without Using Catalan Series */
{a(n) = my(A, M=ceil(sqrt(n+1)));
A = sum(m=0, M, sum(k=0, 2*m, (-1)^k*binomial(2*m-k, k)*(2*m+1)/(2*m-2*k+1) * x^(m^2 + k) ) +x*O(x^n)); polcoeff(A, n)}
for(n=0, 90, print1(a(n), ", "))

Formula

G.f. A(x) = Sum_{n>=0} a(n)*x^n may be obtained from the following expressions; here, C(x) = 1 + x*C(x)^2 is the g.f. of the Catalan numbers (A000108).
(1) A(x) = Sum_{n=-oo..+oo} x^(n^2) * C(x)^(2*n-1).
(2) A(x) = 1/C(x) * Product_{n>=1} (1 + x^(2*n-1)*C(x)^2) * (1 + x^(2*n-1)/C(x)^2) * (1 - x^(2*n)), by the Jacobi triple product identity.
(3) A(x) = 1/C(x) + Sum_{n>=1} x^(n^2) * (C(x)^(2*n-1) + 1/C(x)^(2*n+1)).
(4) A(x) = Sum_{n>=0} Sum_{k=0..n} (-1)^k * binomial(2*n-k, k) * (2*n+1)/(2*n-2*k+1) * x^(n^2 + k).

A356778 G.f.: Sum_{n=-oo..+oo} x^(n^2) * C(x)^(4*n-4), where C(x) = 1 + x*C(x)^2 is the g.f. of the Catalan numbers (A000108).

Original entry on oeis.org

1, -2, -6, 20, -15, -10, 54, -112, 105, -35, -14, 104, -352, 660, -672, 336, -63, -18, 170, -800, 2275, -4004, 4290, -2640, 825, -99, -22, 252, -1520, 5814, -14688, 24752, -27456, 19305, -8008, 1716, -143, -26, 350, -2576, 12397, -40964, 94962, -155040, 176358, -136136, 68068, -20384, 3185
Offset: 0

Views

Author

Paul D. Hanna, Sep 08 2022

Keywords

Examples

			G.f.: A(x) = 1 - 2*x - 6*x^2 + 20*x^3 - 15*x^4 - 10*x^5 + 54*x^6 - 112*x^7 + 105*x^8 - 35*x^9 - 14*x^10 + 104*x^11 - 352*x^12 + 660*x^13 - 672*x^14 + 336*x^15 - 63*x^16 - 18*x^17 + 170*x^18 - 800*x^19 + 2275*x^20 - 4004*x^21 + 4290*x^22 - 2640*x^23 + 825*x^24 - 99*x^25 - 22*x^26 + 252*x^27 - 1520*x^28 + 5814*x^29 - 14688*x^30 + 24752*x^31 - 27456*x^32 + 19305*x^33 - 8008*x^34 + 1716*x^35 - 143*x^36 + ...
such that
A(x) = ... + x^16/C(x)^20 + x^9/C(x)^16 + x^4/C(x)^12 + x/C(x)^8 + 1/C(x)^4 + x + x^4*C(x)^4 + x^9*C(x)^8 + x^16*C(x)^12 + x^25*C(x)^16 + ... + x^(n^2)*C(x)^(4*n-4) + ...
where the Catalan function C(x) = (1 - sqrt(1-4*x))/(2*x) begins
C(x) = 1 + x + 2*x^2 + 5*x^3 + 14*x^4 + 42*x^5 + 132*x^6 + 429*x^7 + 1430*x^8 + 4862*x^9 + ... + A000108(n)*x^n + ...
RELATED TABLE.
This sequence may be written in the form of an irregular triangle that begins:
1,
-2, -6, 20,
-15, -10, 54, -112, 105,
-35, -14, 104, -352, 660, -672, 336,
-63, -18, 170, -800, 2275, -4004, 4290, -2640, 825,
-99, -22, 252, -1520, 5814, -14688, 24752, -27456, 19305, -8008, 1716,
-143, -26, 350, -2576, 12397, -40964, 94962, -155040, 176358, -136136, 68068, -20384, 3185,
-195, -30, 464, -4032, 23400, -95680, 283360, -615296, 980628, -1136960, 940576, -537472, 201552, -45696, 5440,
...
Compare the above to a related table B where B(n,k) = (-1)^k * A034807(4*n,k), for n >= 0, k = 0.. 2*n, and starts as:
1,
1, -4, 2,
1, -8, 20, -16, 2,
1, -12, 54, -112, 105, -36, 2,
1, -16, 104, -352, 660, -672, 336, -64, 2,
1, -20, 170, -800, 2275, -4004, 4290, -2640, 825, -100, 2,
1, -24, 252, -1520, 5814, -14688, 24752, -27456, 19305, -8008, 1716, -144, 2,
...

Links

Crossrefs

Cf. A355341, A355345, A034807, A356777, A000108.

Programs

  • PARI
    /* By Definition: */
{a(n) = my(A, C=1/x*serreverse(x-x^2 +O(x^(n+2))), M=ceil(sqrt(n+1)));
A = sum(m=-M, M, x^(m^2) * C^(4*m-4) ); polcoeff(A, n)}
for(n=0, 50, print1(a(n), ", "))
  • PARI
    /* Without Using Catalan Series - Faster */
{a(n) = my(A, M=ceil(sqrt(n+1)));
A = sum(m=0, M, sum(k=0, 2*m, (-1)^k * (binomial(4*m-k,k) + binomial(4*m-k-1,k-1)) * x^((m-1)^2 + k) ) +x*O(x^n)); polcoeff(A, n)}
for(n=0, 50, print1(a(n), ", "))

Formula

G.f. A(x) = Sum_{n>=0} a(n)*x^n may be obtained from the following expressions; here, C(x) = 1 + x*C(x)^2 is the g.f. of the Catalan numbers (A000108).
(1) A(x) = Sum_{n=-oo..+oo} x^(n^2) * C(x)^(4*n-4).
(2) A(x) = 1/C(x)^4 * Product_{n>=1} (1 + x^(2*n-1)*C(x)^4) * (1 + x^(2*n-1)/C(x)^4) * (1 - x^(2*n)), by the Jacobi triple product identity.
(3) A(x) = 1/C(x)^4 + Sum_{n>=1} x^(n^2) * (C(x)^(4*n-4) + 1/C(x)^(4*n+4)).
(4) A(x) = Sum_{n>=0} Sum_{k=0..2*n} (-1)^k * (binomial(4*n-k,k) + binomial(4*n-k-1,k-1)) * x^((n-1)^2 + k).

A355348 G.f.: Sum_{n=-oo..+oo} x^(n*(n+1)/2) * C(x)^(3*n-3), where C(x) = 1 + x*C(x)^2 is the g.f. of the Catalan numbers (A000108).

Original entry on oeis.org

2, -7, 0, 26, -42, 63, -111, 90, 54, -273, 451, -396, 275, -561, 1287, -1781, 1365, -351, -871, 2938, -5733, 7008, -5172, 2331, -1905, 5835, -14688, 24752, -27455, 19278, -7684, -561, 10251, -32317, 69768, -104652, 107407, -72960, 31293, -10621, 18069, -63783
Offset: 0

Views

Author

Paul D. Hanna, Jul 28 2022

Keywords

Examples

			G.f.: A(x) = 2 - 7*x + 26*x^3 - 42*x^4 + 63*x^5 - 111*x^6 + 90*x^7 + 54*x^8 - 273*x^9 + 451*x^10 - 396*x^11 + 275*x^12 - 561*x^13 + 1287*x^14 - 1781*x^15 + ...
such that
A(x) = ... + x^6/C(x)^15 + x^3/C(x)^12 + x/C(x)^9 + 1/C(x)^6 + 1/C(x)^3 + x + x^3*C(x)^3 + x^6*C(x)^6 + x^10*C(x)^9 + x^15*C(x)^12 + ... + x^(n*(n+1)/2) * C(x)^(3*n-3) + ...
also
A(x) = 1/C(x)^6 * (1 + C(x)^3)*(1 + x/C(x)^3)*(1-x) * (1 + x*C(x)^3)*(1 + x^2/C(x)^3)*(1-x^2) * (1 + x^2*C(x)^3)*(1 + x^3/C(x)^3)*(1-x^3) * (1 + x^3*C(x)^3)*(1 + x^4/C(x)^3)*(1-x^4) * ... * (1 + x^(n-1)*C(x)^3)*(1 + x^n/C(x)^3)*(1-x^n) * ...
where C(x) = 1 + x*C(x)^2 begins
C(x) = 1 + x + 2*x^2 + 5*x^3 + 14*x^4 + 42*x^5 + 132*x^6 + 429*x^7 + 1430*x^8 + ... + A000108(n)*x^n + ...

Links

Crossrefs

Cf. A355341, A355345, A000108.

Programs

  • PARI
    {a(n) = my(A,C=1/x*serreverse(x-x^2 +O(x^(n+2))),M=ceil(sqrt(2*n+9)));
A = sum(m=-M,M, x^(m*(m+1)/2) * C^(3*m-3) ); polcoeff(A,n)}
for(n=0,70,print1(a(n),", "))

Formula

G.f. A(x) = Sum_{n>=0} a(n)*x^n may be obtained from the following expressions; here, C(x) = 1 + x*C(x)^2 is the g.f. of the Catalan numbers (A000108).
(1) A(x) = Sum_{n=-oo..+oo} x^(n*(n+1)/2) * C(x)^(3*n-3).
(2) A(x) = Sum_{n>=0} x^(n*(n+1)/2) * (C(x)^(3*n-3) + 1/C(x)^(3*n+6)).
(3) A(x) = 1/C(x)^6 * Product_{n>=1} (1 + x^(n-1)*C(x)^3) * (1 + x^n/C(x)^3) * (1-x^n), by the Jacobi triple product identity.

A355346 G.f.: A(x,y) = Sum_{n=-oo..+oo} (x*y)^(n*(n+1)/2) * C(x)^(2*n-1), where C(x) = 1 + x*C(x)^2 is the g.f. of the Catalan numbers (A000108).

Original entry on oeis.org

2, -4, 2, -1, -4, 0, -3, 7, 0, 2, -8, 5, 0, -4, 0, -23, 14, 0, 23, 0, 0, -70, 41, 0, 21, 0, 0, 2, -222, 127, 0, 90, 0, 0, -4, 0, -726, 409, 0, 297, 0, 0, 47, 0, 0, -2431, 1355, 0, 1001, 0, 0, 45, 0, 0, 0, -8294, 4587, 0, 3431, 0, 0, 284, 0, 0, 0, 2, -28730, 15795, 0, 11927, 0, 0, 1001, 0, 0, 0, -4, 0, -100776, 55146, 0, 41955, 0, 0, 3640, 0, 0, 0, 79, 0, 0, -357238, 194752, 0, 149072, 0, 0, 13260, 0, 0, 0, 77, 0, 0, 0
Offset: 0

Views

Author

Paul D. Hanna, Jul 25 2022

Keywords

Examples

			G.f.: A(x,y) = 2 + (2*y - 4)*x + (-4*y - 1)*x^2 + (2*y^3 + 7*y - 3)*x^3 + (-4*y^3 + 5*y - 8)*x^4 + (23*y^3 + 14*y - 23)*x^5 + (2*y^6 + 21*y^3 + 41*y - 70)*x^6 + (-4*y^6 + 90*y^3 + 127*y - 222)*x^7 + (47*y^6 + 297*y^3 + 409*y - 726)*x^8 + (45*y^6 + 1001*y^3 + 1355*y - 2431)*x^9 + (2*y^10 + 284*y^6 + 3431*y^3 + 4587*y - 8294)*x^10 + ...
such that
A(x,y) = ... + (x*y)^6/C(x)^9 + (x*y)^3/C(x)^7 + (x*y)/C(x)^5 + 1/C(x)^3 + 1/C(x) + (x*y)*C(x) + (x*y)^3*C(x)^3 + (x*y)^6*C(x)^5 + (x*y)^10*C(x)^7 + (x*y)^15*C(x)^9 + ... + (x*y)^(n*(n+1)/2) * C(x)^(2*n-1) + ...
also
A(x,y) = 1/C(x)^3 * (1 + C(x)^2)*(1 + x*y/C(x)^2)*(1-x) * (1 + x*y*C(x)^2)*(1 + (x*y)^2/C(x)^2)*(1-x^2) * (1 + (x*y)^2*C(x)^2)*(1 + (x*y)^3/C(x)^2)*(1-(x*y)^3) * (1 + (x*y)^3*C(x)^2)*(1 + (x*y)^4/C(x)^2)*(1-(x*y)^4) * ... * (1 + (x*y)^(n-1)*C(x)^2)*(1 + (x*y)^n/C(x)^2)*(1-(x*y)^n) * ...
where C(x) = 1 + x*C(x)^2 begins
C(x) = 1 + x + 2*x^2 + 5*x^3 + 14*x^4 + 42*x^5 + 132*x^6 + 429*x^7 + 1430*x^8 + ... + A000108(n)*x^n + ...
This triangle of coefficients T(n,k) of x^n*y^k in A(x,y), for k = 0..n in row n, n >= 0, begins:
         2;
        -4,       2;
        -1,      -4, 0;
        -3,       7, 0,       2;
        -8,       5, 0,      -4, 0;
       -23,      14, 0,      23, 0, 0;
       -70,      41, 0,      21, 0, 0,      2;
      -222,     127, 0,      90, 0, 0,     -4, 0;
      -726,     409, 0,     297, 0, 0,     47, 0, 0;
     -2431,    1355, 0,    1001, 0, 0,     45, 0, 0, 0;
     -8294,    4587, 0,    3431, 0, 0,    284, 0, 0, 0,    2;
    -28730,   15795, 0,   11927, 0, 0,   1001, 0, 0, 0,   -4, 0;
   -100776,   55146, 0,   41955, 0, 0,   3640, 0, 0, 0,   79, 0, 0;
   -357238,  194752, 0,  149072, 0, 0,  13260, 0, 0, 0,   77, 0, 0, 0;
  -1277788,  694450, 0,  534251, 0, 0,  48450, 0, 0, 0,  692, 0, 0, 0, 0;
  -4605980, 2496790, 0, 1928992, 0, 0, 177649, 0, 0, 0, 2537, 0, 0, 0, 0, 2;
  ...
the row sums of which yield A355345:
[2, -2, -5, 6, -7, 14, -6, -9, 27, -30, 10, -11, 44, -77, 55, -10, -13, 65, -156, 182, -91, ...].
The row sums in turn form the antidiagonals of the rectangular table given by:
n = 0: [  2,  -5,  14,   -30,    55,    -91,    140, ...];
n = 1: [ -2,  -7,  27,   -77,   182,   -378,    714, ...];
n = 2: [  6,  -9,  44,  -156,   450,  -1122,   2508, ...];
n = 3: [ -6, -11,  65,  -275,   935,  -2717,   7007, ...];
n = 4: [ 10, -13,  90,  -442,  1729,  -5733,  16744, ...];
n = 5: [-10, -15, 119,  -665,  2940, -10948,  35700, ...];
n = 6: [ 14, -17, 152,  -952,  4692, -19380,  69768, ...];
n = 7: [-14, -19, 189, -1311,  7125, -32319, 127281, ...];
...
in which row n has g.f.: (-1)^n*(2*n+1) + (1-x)/(1+x)^(2*n+4) for n >= 0.

Crossrefs

Cf. A355345, A000108.

Programs

  • PARI
    {T(n,k) = my(A,C = serreverse(x-x^2 +x^2*O(x^n))/x, M = sqrtint(2*n+9));
A = sum(m=0,n+2, (x*y)^(m*(m+1)/2) * (C^(2*m-1) + 1/C^(2*m+3))); polcoeff(polcoeff(A,n,x),k,y)}
for(n=0,16,for(k=0,n, print1(T(n,k),", "));print(""))

Formula

G.f. A(x,y) = Sum_{n>=0} x^n * Sum_{k=0..n} T(n,k) * y^k may be obtained from the following expressions; here, C(x) = 1 + x*C(x)^2 is the g.f. of the Catalan numbers (A000108).
(1) A(x,y) = Sum_{n=-oo..+oo} (x*y)^(n*(n+1)/2) * C(x)^(2*n-1).
(2) A(x,y) = Sum_{n>=0} (x*y)^(n*(n+1)/2) * (C(x)^(2*n-1) + 1/C(x)^(2*n+3)).
(3) A(x,y) = 1/C(x)^3 * Product_{n>=1} (1 + (x*y)^(n-1)*C(x)^2) * (1 + (x*y)^n/C(x)^2) * (1-(x*y)^n), by the Jacobi triple product identity.

A355347 a(n) = binomial(3*n+3,n) + binomial(3*n+2,n-1) for n >= 0.

Original entry on oeis.org

1, 7, 44, 275, 1729, 10948, 69768, 447051, 2877875, 18599295, 120609840, 784384692, 5114119724, 33417386200, 218786861392, 1434903854139, 9425348845815, 61997934676405, 408323057257500, 2692322893972635, 17770644483690945, 117406930477134480, 776363580147660960
Offset: 0

Views

Author

Paul D. Hanna, Jul 25 2022

Keywords

Comments

A355345(2*n*(n+1)) = (-1)^n * a(n) for n >= 1.
Limit_{n->oo} a(n)/a(n+1) = 4/27.

Examples

			G.f.: A(x) = 1 + 7*x + 44*x^2 + 275*x^3 + 1729*x^4 + 10948*x^5 + 69768*x^6 + 447051*x^7 + 2877875*x^8 + 18599295*x^9 + 120609840*x^10 + ...
such that
A(x) = G(x)^3 * (1 + x*G(x)^2) / (1 - 3*x*G(x)^2)
where G(x) = 1 + x*G(x)^3 begins
G(x) = 1 + x + 3*x^2 + 12*x^3 + 55*x^4 + 273*x^5 + 1428*x^6 + 7752*x^7 + 43263*x^8 + 246675*x^9 + 1430715*x^10 + ... + A001764(n)*x^n + ...

Crossrefs

Cf. A001764, A355345.

Programs

  • PARI
    {a(n) = binomial(3*n+3,n) + binomial(3*n+2,n-1)}
for(n=0,22,print1(a(n),", "))

Formula

G.f.: G(x)^3 * (1 + x*G(x)^2) / (1 - 3*x*G(x)^2), where G(x) = 1 + x*G(x)^3 is the g.f. of A001764.
G.f.: G'(x) * (1 + x*G(x)^2), where G(x) = 1 + x*G(x)^3 is the g.f. of A001764.
a(n) = [x^n] (1+x)/(1-x)^(2*n+4) for n >= 0.

A355864 G.f.: Sum_{n=-oo..+oo} x^(n*(n+1)/2) * C(x)^(4*n-6), where C(x) = 1 + x*C(x)^2 is the g.f. of the Catalan numbers (A000108).

Original entry on oeis.org

2, -14, 28, 26, -203, 427, -741, 1314, -1575, 264, 3201, -7953, 11308, -11440, 13364, -26403, 50479, -68549, 59956, -19930, -50743, 165880, -319635, 436575, -424830, 308193, -258570, 488410, -1122459, 2043162, -2777783, 2771340, -1946892, 726066, 746643, -3157458, 7406770
Offset: 0

Views

Author

Paul D. Hanna, Aug 02 2022

Keywords

Examples

			G.f.: A(x) = 2 - 14*x + 28*x^2 + 26*x^3 - 203*x^4 + 427*x^5 - 741*x^6 + 1314*x^7 - 1575*x^8 + 264*x^9 + 3201*x^10 - 7953*x^11 + 11308*x^12 + ...
such that
A(x) = ... + x^6/C(x)^22 + x^3/C(x)^18 + x/C(x)^14 + 1/C(x)^10 + 1/C(x)^6 + x/C(x)^2 + x^3*C(x)^2 + x^6*C(x)^6 + x^10*C(x)^10 + x^15*C(x)^14 + ... + x^(n*(n+1)/2) * C(x)^(4*n-6) + ...
also
A(x) = 1/C(x)^10 * (1 + C(x)^4)*(1 + x/C(x)^4)*(1-x) * (1 + x*C(x)^4)*(1 + x^2/C(x)^4)*(1-x^2) * (1 + x^2*C(x)^4)*(1 + x^3/C(x)^4)*(1-x^3) * (1 + x^3*C(x)^4)*(1 + x^4/C(x)^4)*(1-x^4) * ... * (1 + x^(n-1)*C(x)^4)*(1 + x^n/C(x)^4)*(1-x^n) * ...
where C(x) = 1 + x*C(x)^2 begins
C(x) = 1 + x + 2*x^2 + 5*x^3 + 14*x^4 + 42*x^5 + 132*x^6 + 429*x^7 + 1430*x^8 + ... + A000108(n)*x^n + ...

Links

Crossrefs

Cf. A355341, A355345, A355348, A000108.

Programs

  • PARI
    {a(n) = my(A, C=1/x*serreverse(x-x^2 +O(x^(n+2))), M=ceil(sqrt(2*n+9)));
A = sum(m=-M, M, x^(m*(m+1)/2) * C^(4*m-6) ); polcoeff(A, n)}
for(n=0, 70, print1(a(n), ", "))

Formula

G.f. A(x) = Sum_{n>=0} a(n)*x^n may be obtained from the following expressions; here, C(x) = 1 + x*C(x)^2 is the g.f. of the Catalan numbers (A000108).
(1) A(x) = 1/C(x)^6 * Sum_{n=-oo..+oo} x^(n*(n+1)/2) * C(x)^(4*n).
(2) A(x) = 1/C(x)^10 * Product_{n>=1} (1 + x^(n-1)*C(x)^4) * (1 + x^n/C(x)^4) * (1-x^n), by the Jacobi triple product identity.

A356779 G.f.: Sum_{n=-oo..+oo} x^(n^2) * C(x)^(6*n-9), where C(x) = 1 + x*C(x)^2 is the g.f. of the Catalan numbers (A000108).

Original entry on oeis.org

1, -7, 9, 60, -265, 429, -189, -812, 2925, -5732, 6980, -4824, -198, 10010, -32298, 69768, -104651, 107373, -72435, 26422, 19656, -115011, 361763, -834900, 1427679, -1797817, 1641447, -1057446, 454155, -69564, -298980, 1307448, -4102104, 9924525, -18599295
Offset: 0

Views

Author

Paul D. Hanna, Sep 08 2022

Keywords

Examples

			G.f.: A(x) = 1 - 7*x + 9*x^2 + 60*x^3 - 265*x^4 + 429*x^5 - 189*x^6 - 812*x^7 + 2925*x^8 - 5732*x^9 + 6980*x^10 - 4824*x^11 - 198*x^12 + 10010*x^13 - 32298*x^14 + 69768*x^15 - 104651*x^16 + 107373*x^17 - 72435*x^18 + 26422*x^19 + 19656*x^20 - 115011*x^21 + 361763*x^22 - 834900*x^23 + 1427679*x^24 - 1797817*x^25 + ...
such that
A(x) = ... + x^16/C(x)^33 + x^9/C(x)^27 + x^4/C(x)^21 + x/C(x)^15 + 1/C(x)^9 + x/C(x)^3 + x^4*C(x)^3 + x^9*C(x)^9 + x^16*C(x)^15 + x^25*C(x)^21 + ... + x^(n^2)*C(x)^(6*n-9) + ...
where the Catalan function C(x) = (1 - sqrt(1-4*x))/(2*x) begins
C(x) = 1 + x + 2*x^2 + 5*x^3 + 14*x^4 + 42*x^5 + 132*x^6 + 429*x^7 + 1430*x^8 + 4862*x^9 + ... + A000108(n)*x^n + ...
RELATED TABLE.
This sequence may be written in the form of an irregular triangle that begins:
1,
-7, 9, 60,
-265, 429, -189, -812, 2925,
-5732, 6980, -4824, -198, 10010, -32298, 69768,
-104651, 107373, -72435, 26422, 19656, -115011, 361763, -834900, 1427679,
-1797817, 1641447, -1057446, 454155, -69564, -298980, 1307448, -4102104, 9924525, -18599295, 26936910,
-29910464, 25109975, -15599955, 6941244, -2013544, -324558, 3717882, -14942570, 46955661, -117679100, 236030652, -378658800, 483841800,
...

Links

Crossrefs

Cf. A356777, A356778, A355341, A355345, A034807, A000108.

Programs

  • PARI
    /* By Definition: */
{a(n) = my(A, C=1/x*serreverse(x-x^2 +O(x^(n+2))), M=ceil(sqrt(n+1)));
A = sum(m=-M, M, x^(m^2) * C^(6*m-9) ); polcoeff(A, n)}
for(n=0, 50, print1(a(n), ", "))

Formula

G.f. A(x) = Sum_{n>=0} a(n)*x^n may be obtained from the following expressions; here, C(x) = 1 + x*C(x)^2 is the g.f. of the Catalan numbers (A000108).
(1) A(x) = Sum_{n=-oo..+oo} x^(n^2) * C(x)^(6*n-9).
(2) A(x) = 1/C(x)^9 * Product_{n>=1} (1 + x^(2*n-1)*C(x)^6) * (1 + x^(2*n-1)/C(x)^6) * (1 - x^(2*n)), by the Jacobi triple product identity.
(3) A(x) = 1/C(x)^9 + Sum_{n>=1} x^(n^2) * (C(x)^(6*n-9) + 1/C(x)^(6*n+9)).
Showing 1-7 of 7 results.

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