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.

A356500 Coefficients T(n,k) of x^n*y^k in A(x,y) for n >= 0, k = 0..3*n+1, where A(x,y) satisfies: y = Sum_{n=-oo..+oo} (-x)^(n^2) * A(x,y)^((n-1)^2), as an irregular triangle read by rows.

Original entry on oeis.org

0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 4, 0, 0, 0, 4, 0, 0, 6, 0, 0, 0, 28, 0, 0, 0, 22, 0, 3, 0, 0, 0, 84, 0, 0, 0, 219, 0, 0, 0, 140, 0, 0, 0, 0, 135, 0, 0, 0, 981, 0, 0, 0, 1807, 0, 0, 0, 969, 0, 0, 0, 120, 0, 0, 0, 2568, 0, 0, 0, 10764, 0, 0, 0, 15368, 0, 0, 0, 7084, 0, 0, 54, 0, 0, 0, 4284, 0, 0, 0, 38896, 0, 0, 0, 114240, 0, 0, 0, 133266, 0, 0, 0, 53820, 0, 9, 0, 0, 0, 4662, 0, 0, 0, 94390, 0, 0, 0, 525980, 0, 0, 0, 1187433, 0, 0, 0, 1171390, 0, 0, 0, 420732
Offset: 0

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Author

Paul D. Hanna, Aug 09 2022

Keywords

Comments

T(n, 3*n+1) = [x^n*y^(3*n+1)] A(x,y) = binomial(4*n, n)/(3*n + 1) = A002293(n) for n >= 0, where g.f. G(x) of A002293 satisfies: G(x) = 1 + x*G(x)^4.
T(4*n, 1) = A000716(n) for n >= 0 (nonzero terms in column 1).
T(4*n+3, 2) = [x^(4*n+3)*y^2] A(x,y) = 2 * A354655(n+1) for n >= 0, where A354655 equals column 2 of triangle A354650.
T(4*n+2, 3) = [x^(4*n+2)*y^3] A(x,y) = 4 * A354656(n+1) for n >= 0, where A354656 equals column 3 of triangle A354650.
T(2*n, 2*n+1) = A356504(n), for n >= 0.
T(2*n+1, 2*n) = A356505(n) for n >= 0.
T(3*n, n+1) = A356506(n) for n >= 0.
T(3*n+1, n) = A355365(n) where A355365 is the central terms of A355360 = A355360(2*n,n).
Sum_{k=0..3*n+1} T(n, k) = A354248(n) for n >= 0 (row sums).
Sum_{k=0..3*n+1} T(n, k) * 2^k = A356502(n) for n >= 0.
Sum_{k=0..3*n+1} T(n, k) * 3^k = A356503(n) for n >= 0.
Sum_{k=0..3*n+1} T(4*n+1-k, k) = A355872(n+1) for n >= 0 (nonzero antidiagonal sums).
SPECIFIC VALUES.
(V.1) 1 = A(x,y) at x = -exp(-Pi) and y = Pi^(1/4)/gamma(3/4).
(V.2) 1 = A(x,y) at x = -exp(-2*Pi) and y = Pi^(1/4)/gamma(3/4) * (6 + 4*sqrt(2))^(1/4)/2.
(V.3) 1 = A(x,y) at x = -exp(-3*Pi) and y = Pi^(1/4)/gamma(3/4) * (27 + 18*sqrt(3))^(1/4)/3.
(V.4) 1 = A(x,y) at x = -exp(-4*Pi) and y = Pi^(1/4)/gamma(3/4) * (8^(1/4) + 2)/4.
(V.5) 1 = A(x,y) at x = -exp(-sqrt(3)*Pi) and y = gamma(4/3)^(3/2)*3^(13/8)/(Pi*2^(2/3)).

Examples

			G.f.: A(x,y) = y + x*(1 + y^4) + x^2*(4*y^3 + 4*y^7) + x^3*(6*y^2 + 28*y^6 + 22*y^10) + x^4*(3*y + 84*y^5 + 219*y^9 + 140*y^13) + x^5*(135*y^4 + 981*y^8 + 1807*y^12 + 969*y^16) + x^6*(120*y^3 + 2568*y^7 + 10764*y^11 + 15368*y^15 + 7084*y^19) + x^7*(54*y^2 + 4284*y^6 + 38896*y^10 + 114240*y^14 + 133266*y^18 + 53820*y^22) + x^8*(9*y + 4662*y^5 + 94390*y^9 + 525980*y^13 + 1187433*y^17 + 1171390*y^21 + 420732*y^25) + x^9*(3250*y^4 + 160965*y^8 + 1670942*y^12 + 6640711*y^16 + 12167001*y^20 + 10399545*y^24 + 3362260*y^28) + ...
such that A = A(x,y) satisfies
y = ... + x^16*A^25 - x^9*A^16 + x^4*A^9 - x*A^4 + A - x + x^4*A - x^9*A^4 + x^16*A^9 - x^25*A^16 +- ... + (-x)^(n^2) * A(x,y)^((n-1)^2) + ...
This irregular triangle of coefficients T(n,k) of x^n*y^k in A(x,y) for n >= 0, k = 0..3*n+1, begins:
  n = 0: [0, 1];
  n = 1: [1, 0, 0, 0, 1];
  n = 2: [0, 0, 0, 4, 0, 0, 0, 4];
  n = 3: [0, 0, 6, 0, 0, 0, 28, 0, 0, 0, 22];
  n = 4: [0, 3, 0, 0, 0, 84, 0, 0, 0, 219, 0, 0, 0, 140];
  n = 5: [0, 0, 0, 0, 135, 0, 0, 0, 981, 0, 0, 0, 1807, 0, 0, 0, 969];
  n = 6: [0, 0, 0, 120, 0, 0, 0, 2568, 0, 0, 0, 10764, 0, 0, 0, 15368, 0, 0, 0, 7084];
  n = 7: [0, 0, 54, 0, 0, 0, 4284, 0, 0, 0, 38896, 0, 0, 0, 114240, 0, 0, 0, 133266, 0, 0, 0, 53820];
  n = 8: [0, 9, 0, 0, 0, 4662, 0, 0, 0, 94390, 0, 0, 0, 525980, 0, 0, 0, 1187433, 0, 0, 0, 1171390, 0, 0, 0, 420732];
  n = 9: [0, 0, 0, 0, 3250, 0, 0, 0, 160965, 0, 0, 0, 1670942, 0, 0, 0, 6640711, 0, 0, 0, 12167001, 0, 0, 0, 10399545, 0, 0, 0, 3362260];
  ...
Reading this triangle by nonzero antidiagonals [x^(4*n+1-k)*y^k] A(x,y) for n >= 0, k = 0..3*n+1, yields triangle A356501:
  [1, 1];
  [0, 3, 6, 4, 1];
  [0, 9, 54, 120, 135, 84, 28, 4];
  [0, 22, 294, 1360, 3250, 4662, 4284, 2568, 981, 219, 22];
  [0, 51, 1260, 10120, 41405, 103020, 170324, 196172, 160965, 94390, 38896, 10764, 1807, 140];
  [0, 108, 4590, 58380, 368145, 1404102, 3587696, 6515712, 8715465, 8763645, 6684744, 3863496, 1670942, 525980, 114240, 15368, 969];
  ...
		

Crossrefs

Programs

  • PARI
    {T(n,k) = my(A=[y],M); for(i=1,n, A = concat(A,0); M = ceil(sqrt(n+1));
    A[#A] = -polcoeff( sum(m=-M,M, (-x)^(m^2)*Ser(A)^((m-1)^2)), #A-1)); polcoeff(A[n+1],k,y) }
    for(n=0,9, for(k=0,3*n+1, print1(T(n,k),", "));print(""))

Formula

G.f. A(x,y) = Sum_{n>=0} Sum_{k=0..3*n+1} T(n,k) * x^n * y^k satisfies:
(1) y = Sum_{n=-oo..+oo} (-x)^(n^2) * A(x,y)^((n+1)^2).
(2) y = A(x,y) * Product_{n>=1} (1 - x^(2*n)*A(x,y)^(2*n)) * (1 - x^(2*n-1)*A(x,y)^(2*n+1)) * (1 - x^(2*n-1)*A(x,y)^(2*n-3)), by the Jacobi triple product identity.
(3) y = (-x) * Product_{n>=1} (1 - x^(2*n)*A(x,y)^(2*n)) * (1 - x^(2*n+1)*A(x,y)^(2*n-1)) * (1 - x^(2*n-3)*A(x,y)^(2*n-1)), by the Jacobi triple product identity.
(4) y = A(x, F(x,y)) where F(x,y) = Sum_{n=-oo..+oo} (-x)^(n^2) * y^((n-1)^2).
(5) 1 = A(x, theta_4(x)) where theta_4(x) = 1 + 2*Sum_{n>=1} (-1)^n * x^(n^2) is a Jacobi theta function.

A356502 G.f. A(x) satisfies: 2 = Sum_{n=-oo..+oo} (-x)^(n^2) * A(x)^((n-1)^2).

Original entry on oeis.org

2, 17, 544, 24344, 1261702, 71159152, 4240009152, 262584135640, 16734002688722, 1090225325371424, 72285357987696768, 4861658409827006872, 330874470176939132844, 22744684876060771599568, 1576898258893213475814464, 110136698483814852518084528, 7742091796859524187452564262
Offset: 0

Views

Author

Paul D. Hanna, Aug 09 2022

Keywords

Examples

			G.f.: A(x) = 2 + 17*x + 544*x^2 + 24344*x^3 + 1261702*x^4 + 71159152*x^5 + 4240009152*x^6 + 262584135640*x^7 + 16734002688722*x^8 + ...
such that A = A(x) satisfies
2 = ... + x^16*A^25 - x^9*A^16 + x^4*A^9 - x*A^4 + A - x + x^4*A - x^9*A^4 + x^16*A^9 - x^25*A^16 +- ... + (-x)^(n^2) * A(x,y)^((n-1)^2) + ...
		

Crossrefs

Programs

  • Mathematica
    (* Calculation of constant d: *) 1/r /. FindRoot[{k == r^4*s^2 * QPochhammer[1/(r^3*s), r^2*s^2] * QPochhammer[r/s, r^2*s^2] * QPochhammer[r^2*s^2, r^2*s^2]/((r - s)*(-1 + r^3*s)), 1/r^3*(k*(1 + r^4 - 2*r/s) + 2*r^6*s^3*QPochhammer[r/s, r^2*s^2] * QPochhammer[r^2*s^2, r^2*s^2]* Derivative[0, 1][QPochhammer][1/(r^3*s), r^2*s^2] + 2*k*r^2*(r - s)*s*(-1 + r^3*s) * Derivative[0, 1][QPochhammer][r/s, r^2*s^2]/ QPochhammer[r/s, r^2*s^2] + 1/s*k*(r - s)*(-1 + r^3*s) * (1/ Log[r^2*s^2]*(-2*QPolyGamma[0, 1, r^2*s^2] + QPolyGamma[0, Log[1/(r^3*s)] / Log[r^2*s^2], r^2*s^2] + QPolyGamma[0, Log[r/s] / Log[r^2*s^2], r^2*s^2]) + 2*r^2*s^2 * Derivative[0, 1][QPochhammer][r^2*s^2, r^2*s^2] / QPochhammer[r^2*s^2, r^2*s^2])) == 0} /. k -> 2, {r, 1/75}, {s, 2}, WorkingPrecision -> 70] (* Vaclav Kotesovec, Jan 18 2024 *)
  • PARI
    {a(n) = my(A=[2],M); for(i=1,n, A = concat(A,0); M = ceil(sqrt(n+1));
    A[#A] = -polcoeff( sum(m=-M,M, (-x)^(m^2)*Ser(A)^((m-1)^2)), #A-1)); H=A; A[n+1]}
    for(n=0,20,print1(a(n),", "))

Formula

G.f. A(x) satisfies:
(1) 2 = Sum_{n=-oo..+oo} (-x)^(n^2) * A(x)^((n+1)^2).
(2) 2 = A(x) * Product_{n>=1} (1 - x^(2*n)*A(x)^(2*n)) * (1 - x^(2*n-1)*A(x)^(2*n+1)) * (1 - x^(2*n-1)*A(x)^(2*n-3)), by the Jacobi triple product identity.
(3) 2 = (-x) * Product_{n>=1} (1 - x^(2*n)*A(x)^(2*n)) * (1 - x^(2*n+1)*A(x)^(2*n-1)) * (1 - x^(2*n-3)*A(x)^(2*n-1)), by the Jacobi triple product identity.
a(n) ~ c * d^n / n^(3/2), where d = 77.309779325704779292317107617559471210592218708634855530355675234... and c = 0.31219183409397424726366930735250286274022579073644627976468... - Vaclav Kotesovec, Mar 19 2023

A356503 G.f. A(x) satisfies: 3 = Sum_{n=-oo..+oo} (-x)^(n^2) * A(x)^((n-1)^2).

Original entry on oeis.org

3, 82, 8856, 1319544, 227536218, 42679033812, 8455886664768, 1741107313315440, 368888770098828828, 79897573332771325074, 17610753240158104125072, 3937441977622780631428392, 890818276864624495645873656, 203562312272030478854160019188, 46914726894168080421554447339136
Offset: 0

Views

Author

Paul D. Hanna, Aug 09 2022

Keywords

Examples

			G.f.: A(x) = 3 + 82*x + 8856*x^2 + 1319544*x^3 + 227536218*x^4 + 42679033812*x^5 + 8455886664768*x^6 + 1741107313315440*x^7 + 368888770098828828*x^8 + ...
such that A = A(x) satisfies
3 = ... + x^16*A^25 - x^9*A^16 + x^4*A^9 - x*A^4 + A - x + x^4*A - x^9*A^4 + x^16*A^9 - x^25*A^16 +- ... + (-x)^(n^2) * A(x,y)^((n-1)^2) + ...
		

Crossrefs

Programs

  • Mathematica
    (* Calculation of constant d: *) 1/r /. FindRoot[{k == r^4*s^2 * QPochhammer[1/(r^3*s), r^2*s^2] * QPochhammer[r/s, r^2*s^2] * QPochhammer[r^2*s^2, r^2*s^2]/((r - s)*(-1 + r^3*s)), 1/r^3*(k*(1 + r^4 - 2*r/s) + 2*r^6*s^3*QPochhammer[r/s, r^2*s^2] * QPochhammer[r^2*s^2, r^2*s^2]* Derivative[0, 1][QPochhammer][1/(r^3*s), r^2*s^2] + 2*k*r^2*(r - s)*s*(-1 + r^3*s) * Derivative[0, 1][QPochhammer][r/s, r^2*s^2]/ QPochhammer[r/s, r^2*s^2] + 1/s*k*(r - s)*(-1 + r^3*s) * (1/ Log[r^2*s^2]*(-2*QPolyGamma[0, 1, r^2*s^2] + QPolyGamma[0, Log[1/(r^3*s)] / Log[r^2*s^2], r^2*s^2] + QPolyGamma[0, Log[r/s] / Log[r^2*s^2], r^2*s^2]) + 2*r^2*s^2 * Derivative[0, 1][QPochhammer][r^2*s^2, r^2*s^2] / QPochhammer[r^2*s^2, r^2*s^2])) == 0} /. k -> 3, {r, 1/250}, {s, 2}, WorkingPrecision -> 70] (* Vaclav Kotesovec, Jan 18 2024 *)
  • PARI
    {a(n) = my(A=[3],M); for(i=1,n, A = concat(A,0); M = ceil(sqrt(n+1));
    A[#A] = -polcoeff( sum(m=-M,M, (-x)^(m^2)*Ser(A)^((m-1)^2)), #A-1)); H=A; A[n+1]}
    for(n=0,20,print1(a(n),", "))

Formula

G.f. A(x) satisfies:
(1) 3 = Sum_{n=-oo..+oo} (-x)^(n^2) * A(x)^((n+1)^2).
(2) 3 = A(x) * Product_{n>=1} (1 - x^(2*n)*A(x)^(2*n)) * (1 - x^(2*n-1)*A(x)^(2*n+1)) * (1 - x^(2*n-1)*A(x)^(2*n-3)), by the Jacobi triple product identity.
(3) 3 = (-x) * Product_{n>=1} (1 - x^(2*n)*A(x)^(2*n)) * (1 - x^(2*n+1)*A(x)^(2*n-1)) * (1 - x^(2*n-3)*A(x)^(2*n-1)), by the Jacobi triple product identity.
a(n) ~ c * d^n / n^(3/2), where d = 256.98186313678886207367060740797984009618789137465012036784040337275... and c = 0.462191657806050531963307936402124127070124175540050112607444087... - Vaclav Kotesovec, Mar 19 2023

A355349 G.f. A(x) satisfies: 2 = Sum_{n=-oo..+oo} (-x)^(n*(n-1)/2) * A(x)^(n^2).

Original entry on oeis.org

1, 2, 10, 76, 678, 6608, 68170, 731638, 8084692, 91361298, 1050937008, 12264790410, 144856757032, 1728197200206, 20796217437806, 252117655811806, 3076371017010508, 37753163861001044, 465657991700212170, 5769586313420410060, 71777257553636752194
Offset: 0

Views

Author

Paul D. Hanna, Aug 02 2022

Keywords

Examples

			G.f.: A(x) = 1 + 2*x + 10*x^2 + 76*x^3 + 678*x^4 + 6608*x^5 + 68170*x^6 + 731638*x^7 + 8084692*x^8 + 91361298*x^9 + 1050937008*x^10 + ...
where
2 = ... + x^6*A(x)^9 - x^3*A(x)^4 - x*A(x) + A(x) + 1 - x*A(x) - x^3*A(x)^4 + x^6*A(x)^9 + x^10*A(x)^16 - x^15*A(x)^25 - x^21*A(x)^36 ++-- ... (-x)^(n*(n-1)/2) * A(x)^(n^2) + ...
		

Crossrefs

Programs

  • Mathematica
    (* Calculation of constant d: *) 1/r /. FindRoot[{r*s^2*QPochhammer[-1/s, -r*s^2]* QPochhammer[1/(r*s), -r*s^2]* QPochhammer[-r*s^2]/((1 + s)*(-1 + r*s)) == 2, (4 + 2*s - 2*r*s)/(r*s^2) + 2*r*s^2*QPochhammer[1/(r*s), -r*s^2]* QPochhammer[-r*s^2] * Derivative[0, 1][QPochhammer][-1/s, -r*s^2] + 4*(1 + s)*(-1 + r*s)* Derivative[0, 1][QPochhammer][1/(r*s), -r*s^2] / QPochhammer[1/(r*s), -r*s^2] + 2*(1 + s)*(-1 + r*s) * ((2*QPolyGamma[0, 1, -r*s^2] - QPolyGamma[0, Log[-1/s]/Log[-r*s^2], -r*s^2] - QPolyGamma[0, Log[1/(r*s)]/Log[-r*s^2], -r*s^2])/(r*s^2* Log[-r*s^2]) + (2*Derivative[0, 1][QPochhammer][-r*s^2, -r*s^2])/ QPochhammer[-r*s^2]) == 0}, {r, 1/12}, {s, 3/2}, WorkingPrecision -> 70] (* Vaclav Kotesovec, Jan 31 2024 *)
  • PARI
    {a(n) = my(A=[1]); for(i=1,n, A=concat(A,0); M=ceil(sqrt(2*n));
    A[#A] = -polcoeff( sum(m=-M,M, (-x)^(m*(m-1)/2) * Ser(A)^(m^2)),#A-1));A[n+1]}
    for(n=0,20,print1(a(n),", "))

Formula

G.f. A(x) satisfies:
(1) 2 = Sum_{n=-oo..+oo} (-x)^(n*(n-1)/2) * A(x)^(n^2).
(2) 2 = Product_{n>=1} (1 - (-x)^n*A(x)^(2*n)) * (1 + (-x)^(n-1)*A(x)^(2*n-1)) * (1 + (-x)^n*A(x)^(2*n-1)), by the Jacobi triple product identity.
From Vaclav Kotesovec, Jan 31 2024: (Start)
Formula (2) can be rewritten as the functional equation QPochhammer(-x*y^2) * QPochhammer(1/(x*y), -x*y^2)/(1 - 1/(x*y)) * QPochhammer(-1/y, -x*y^2)/(1 + 1/y) = 2.
a(n) ~ c * d^n / n^(3/2), where d = 13.4235502463317299100709807099986120871056759637108569... and c = 0.1810118197770993236368884418746617625188562698029... (End)
Showing 1-4 of 4 results.