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.

A357791 a(n) = coefficient of x^n in A(x) such that: x = Sum_{n=-oo..+oo} x^n * (1 - x^n * A(-x)^n)^n.

Original entry on oeis.org

1, 1, 2, 5, 21, 88, 377, 1654, 7424, 34000, 158274, 746525, 3559456, 17128250, 83078147, 405754479, 1993777057, 9849668910, 48892589632, 243739139810, 1219789105228, 6125813250402, 30862120708266, 155937956267432, 790019313067409, 4012282344217699, 20423575546661000
Offset: 0

Views

Author

Paul D. Hanna, Dec 24 2022

Keywords

Comments

Related identity: 0 = Sum_{n=-oo..+oo} x^n * (y - x^n)^n, which holds formally for all y.

Examples

			G.f.: A(x) = 1 + x + 2*x^2 + 5*x^3 + 21*x^4 + 88*x^5 + 377*x^6 + 1654*x^7 + 7424*x^8 + 34000*x^9 + 158274*x^10 + 746525*x^11 + 3559456*x^12 + ...
SPECIFIC VALUES.
A(x) = 3/2 at x = 0.1850570503493984408934312903280642188437354418734...
A(1/6) = 1.3085832721715442420948608003299892250459754159045...
		

Crossrefs

Programs

  • PARI
    {a(n) = my(A=[1]); for(i=1, n, A = concat(A, 0);
    A[#A] = polcoeff(x + sum(n=-#A, #A, (-x)^n * (1 - (-x)^n * Ser(A)^n )^n ), #A-1) ); A[n+1]}
    for(n=0, 30, print1(a(n), ", "))

Formula

G.f. A(x) = Sum_{n>=0} a(n)*x^n satisfies the following.
(1) x = Sum_{n=-oo..+oo} x^n * (1 - x^n * A(-x)^n)^n.
(2) x = Sum_{n=-oo..+oo} (-1)^n * x^(n*(n-1)) * A(-x)^(n^2) / (1 - x^n*A(-x)^n)^n.
a(n) ~ c * d^n / n^(3/2), where d = 5.390297559554269719991046... and c = 0.267652299887938085649... - Vaclav Kotesovec, Dec 25 2022

A359922 a(n) = coefficient of x^n in A(x) where x = Sum_{n=-oo..+oo} (-1)^(n-1) * x^n * (2 + x^n*A(x)^n)^n.

Original entry on oeis.org

1, 1, 4, 9, 42, 187, 775, 3470, 16085, 76521, 368274, 1791494, 8829531, 43964379, 220667042, 1115235384, 5671532510, 29004157940, 149056379047, 769368598912, 3986831368824, 20733495321171, 108175116519808, 566067951728994, 2970221822319878, 15624080964153005
Offset: 0

Views

Author

Paul D. Hanna, Jan 18 2023

Keywords

Examples

			G.f.: A(x) = 1 + x + 4*x^2 + 9*x^3 + 42*x^4 + 187*x^5 + 775*x^6 + 3470*x^7 + 16085*x^8 + 76521*x^9 + 368274*x^10 + ...
where
x = ... + x^6*A(x)^9/(1 + 2*x^3*A(x)^3)^3 - x^2*A(x)^4/(1 + 2*x^2*A(x)^2)^2 + A(x)/(1 + 2*x*A(x)) - 1 + x*(2 + x*A(x)) - x^2*(2 + x^2*A(x)^2)^2 + x^3*(2 + x^3*A(x)^3)^3 + ... + (-1)^(n-1) * x^n * (2 + x^n*A(x)^n)^n + ...
		

Crossrefs

Programs

  • PARI
    {a(n) = my(A=[1]); for(i=1, n, A = concat(A, 0);
    A[#A] = polcoeff(x - sum(m=-#A, #A, (-1)^(m-1) * x^m * (2 + (x*Ser(A))^m)^m ), #A-1)); A[n+1]}
    for(n=0, 30, print1(a(n), ", "))

Formula

G.f. A(x) = Sum_{n>=0} a(n)*x^n satisfies:
(1) x = Sum_{n=-oo..+oo} (-1)^(n-1) * x^n * (2 + x^n*A(x)^n)^n.
(2) x = Sum_{n=-oo..+oo} (-1)^(n-1) * x^(n*(n-1)) * A(x)^(n^2) / (1 + 2*x^n*A(x)^n)^n.

A359923 a(n) = coefficient of x^n in A(x) where x = Sum_{n=-oo..+oo} (-1)^(n-1) * x^n * (3 + x^n*A(x)^n)^n.

Original entry on oeis.org

1, 1, 6, 15, 69, 376, 1741, 8860, 46044, 245074, 1336538, 7337135, 40736876, 228625148, 1293530435, 7372491383, 42275811853, 243742895280, 1412310750812, 8219298313118, 48023377286364, 281592177442072, 1656522460985914, 9773791391488278, 57824226906859849
Offset: 0

Views

Author

Paul D. Hanna, Jan 18 2023

Keywords

Examples

			G.f.: A(x) = 1 + x + 6*x^2 + 15*x^3 + 69*x^4 + 376*x^5 + 1741*x^6 + 8860*x^7 + 46044*x^8 + 245074*x^9 + 1336538*x^10 + ...
where
x = ... + x^6*A(x)^9/(1 + 3*x^3*A(x)^3)^3 - x^2*A(x)^4/(1 + 3*x^2*A(x)^2)^2 + A(x)/(1 + 3*x*A(x)) - 1 + x*(3 + x*A(x)) - x^2*(3 + x^2*A(x)^2)^2 + x^3*(3 + x^3*A(x)^3)^3 + ... + (-1)^(n-1) * x^n * (3 + x^n*A(x)^n)^n + ...
		

Crossrefs

Programs

  • PARI
    {a(n) = my(A=[1]); for(i=1, n, A = concat(A, 0);
    A[#A] = polcoeff(x - sum(m=-#A, #A, (-1)^(m-1) * x^m * (3 + (x*Ser(A))^m)^m ), #A-1)); A[n+1]}
    for(n=0, 30, print1(a(n), ", "))

Formula

G.f. A(x) = Sum_{n>=0} a(n)*x^n satisfies:
(1) x = Sum_{n=-oo..+oo} (-1)^(n-1) * x^n * (3 + x^n*A(x)^n)^n.
(2) x = Sum_{n=-oo..+oo} (-1)^(n-1) * x^(n*(n-1)) * A(x)^(n^2) / (1 + 3*x^n*A(x)^n)^n.

A359669 a(n) = coefficient of x^n in A(x) where x = Sum_{n=-oo..+oo} (-1)^(n-1) * x^(n*(n+1)) * A(x)^(n^2).

Original entry on oeis.org

1, 1, 0, 3, 6, 13, 55, 142, 429, 1495, 4538, 14894, 50279, 164189, 554402, 1883870, 6371434, 21854442, 75183191, 259137380, 899092908, 3127293679, 10907931688, 38188033950, 133998312862, 471339759941, 1662075700667, 5872497411731, 20790187564837, 73741279736768
Offset: 0

Views

Author

Paul D. Hanna, Jan 17 2023

Keywords

Crossrefs

Cf. A359672.

Programs

  • PARI
    {a(n) = my(A=[1]); for(i=1, n, A = concat(A, 0);
    A[#A] = polcoeff(x - sum(m=-#A, #A, (-1)^(m-1) * x^(m*(m+1)) * Ser(A)^(m^2) ), #A-1)); A[n+1]}
    for(n=0, 30, print1(a(n), ", "))

Formula

G.f. A(x) = Sum_{n>=0} a(n)*x^n satisfies:
(1) x = Sum_{n=-oo..+oo} (-1)^(n-1) * x^(n*(n+1)) * A(x)^(n^2).
(2) -x = Product_{n>=1} (1 - x^(2*n)*A(x)^(2*n-1)) * (1 - x^(2*n-2)*A(x)^(2*n-1)) * (1 - x^(2*n)*A(x)^(2*n)), due to the Jacobi triple product identity.
Showing 1-4 of 4 results.