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.

A107092 G.f. A(x) satisfies A(x)^3 = A(x^3) + 3*x.

Original entry on oeis.org

1, 1, -1, 2, -4, 9, -22, 55, -142, 376, -1011, 2758, -7614, 21220, -59630, 168759, -480533, 1375676, -3957075, 11430582, -33144264, 96434321, -281447954, 823734157, -2417092933, 7109265120, -20955593252, 61893804180, -183148075432, 542885589115, -1611809502764, 4792612539375
Offset: 0

Views

Author

Paul D. Hanna, May 11 2005

Keywords

Comments

Self-convolution cube is A107093.

Examples

			A(x)^3 = 1 + 3*x + x^3 - x^6 + 2*x^9 - 4*x^12 + 9*x^15 - 22*x^18 +...
A(x^3) = 1 + x^3 - x^6 + 2*x^9 - 4*x^12 + 9*x^15 - 22*x^18+...
		

Crossrefs

Programs

  • PARI
    {a(n)=local(A=1+x);for(i=1,n,A=(subst(A,x,x^3)+3*x+x*O(x^n))^(1/3)); polcoeff(A,n,x)}

A352704 G.f. A(x) satisfies: (1 - x*A(x))^5 = 1 - 5*x - x^5*A(x^5).

Original entry on oeis.org

1, 2, 6, 21, 80, 320, 1326, 5637, 24434, 107542, 479196, 2157045, 9792702, 44780606, 206055346, 953305632, 4431463863, 20686696920, 96931500840, 455722378776, 2149086843549, 10162544469252, 48176923330632, 228913129263389, 1089973058779915, 5199987220813564
Offset: 0

Views

Author

Paul D. Hanna, Mar 29 2022

Keywords

Comments

Essentially an unsigned version of A352703 (after dropping the initial term).

Examples

			G.f.: A(x) = 1 + 2*x + 6*x^2 + 21*x^3 + 80*x^4 + 320*x^5 + 1326*x^6 + 5637*x^7 + 24434*x^8 + 107542*x^9 + 479196*x^10 + ...
where
(1 - x*A(x))^5 = 1 - 5*x - x^5 - 2*x^10 - 6*x^15 - 21*x^20 - 80*x^25 - 320*x^30 - 1326*x^35 - 5637*x^40 - 24434*x^45 - 107542*x^50 + ...
also
(1 - 5*x - x^5*A(x^5))^(1/5) = 1 - x - 2*x^2 - 6*x^3 - 21*x^4 - 80*x^5 - 320*x^6 - 1326*x^7 - 5637*x^8 - 24434*x^9 - 107542*x^10 + ...
which equals 1 - x*A(x).
		

Crossrefs

Programs

  • PARI
    {a(n) = my(A=1+2*x); for(i=1,n,
    A = (1 - (1 - 5*x - x^5*subst(A,x,x^5) + x*O(x^(n+1)))^(1/5))/x);
    polcoeff(A,n)}
    for(n=0,30,print1(a(n),", "))

Formula

G.f. A(x) satisfies:
(1) (1 + x*A(-x))^5 = 1 + 5*x + x^5*A(-x^5).
(2) A(x) = (1 - (1 - 5*x - x^5*A(x^5))^(1/5))/x.
(3) A(x)^5 = A(x^5) (mod 5).

A352705 G.f. A(x) satisfies: A(x)^7 = A(x^7) + 7*x.

Original entry on oeis.org

1, 1, -3, 13, -65, 351, -1989, 11650, -69900, 427167, -2648438, 16612947, -105215448, 671760933, -4318468134, 27926126553, -181520036178, 1185220461867, -7769787812787, 51117085998498, -337373170647840, 2233091755252871, -14819626692452231, 98582852467595847
Offset: 0

Views

Author

Paul D. Hanna, Mar 29 2022

Keywords

Comments

Not the same as A106227.

Examples

			G.f.: A(x) = 1 + x - 3*x^2 + 13*x^3 - 65*x^4 + 351*x^5 - 1989*x^6 + 11650*x^7 - 69900*x^8 + 427167*x^9 - 2648438*x^10 + ...
such that A(x)^7 = A(x^7) + 7*x, as illustrated by:
A(x)^7 = 1 + 7*x + x^7 - 3*x^14 + 13*x^21 - 65*x^28 + 351*x^35 - 1989*x^42 + 11650*x^49 - 69900*x^56 + 427167*x^63 - 2648438*x^70 + ...
		

Crossrefs

Programs

  • PARI
    {a(n) = my(A=1+x); for(i=1,n,
    A = (subst(A,x,x^7) + 7*x + x*O(x^n))^(1/7));
    polcoeff(A,n)}
    for(n=0,30,print1(a(n),", "))

A370545 Expansion of g.f. A(x) satisfying A(x) = A( x^5 + 5*A(x)^6 )^(1/5).

Original entry on oeis.org

1, 1, 4, 21, 125, 801, 5388, 37518, 268109, 1955000, 14487754, 108794169, 826054062, 6331064385, 48914088750, 380555960864, 2978892961194, 23444095375593, 185394136871818, 1472396312841250, 11739089289817538, 93921736129064325, 753845680317416682, 6068255413854119432
Offset: 1

Views

Author

Paul D. Hanna, Mar 26 2024

Keywords

Comments

Compare the g.f. to the following identities:
(1) C(x) = C( x^2 + 2*x*C(x)^2 )^(1/2),
(2) C(x) = C( x^3 + 3*x*C(x)^3 )^(1/3),
where C(x) = x + C(x)^2 is a g.f. of the Catalan numbers (A000108).

Examples

			G.f.: A(x) = x + x^2 + 4*x^3 + 21*x^4 + 125*x^5 + 801*x^6 + 5388*x^7 + 37518*x^8 + 268109*x^9 + 1955000*x^10 + 14487754*x^11 + 108794169*x^12 + ...
where A(x)^5 = A( x^5 + 5*A(x)^6 ).
RELATED SERIES.
A(x)^5 = x^5 + 5*x^6 + 30*x^7 + 195*x^8 + 1330*x^9 + 9376*x^10 + 67720*x^11 + ...
A(x)^6 = x^6 + 6*x^7 + 39*x^8 + 266*x^9 + 1875*x^10 + 13542*x^11 + 99654*x^12 + ...
Let B(x) be the series reversion of A(x), A(B(x)) = x, which begins
B(x) = x - x^2 - 2*x^3 - 6*x^4 - 21*x^5 - 80*x^6 - 320*x^7 - 1326*x^8 - 5637*x^9 - 24434*x^10 - ... + (-1)^(n-1)*A352703(n-1)*x^n + ...
then B(x)^5 + 5*x^6 = B(x^5).
Let C(x) = x^2/B(x) = x + x^2 + 3*x^3 + 11*x^4 + 44*x^5 + 185*x^6 + 802*x^7 + 3553*x^8 + 15994*x^9 + 72886*x^10 + ... + A091200(n-1)*x^n + ...
where A(x^2/C(x)) = x and C(A(x)) = A(x)^2/x,
then C(x)^5 = C(x^5)/(1 - 5*C(x^5)/x^4).
		

Crossrefs

Programs

  • PARI
    {a(n) = my(A=x+x^2); for(m=1, n, A=truncate(A); A = subst(A, x, x^5 + 5*A^6 +x^5*O(x^m))^(1/5) ); polcoeff(A, n)}
    for(n=1, 40, print1(a(n), ", "))
Showing 1-4 of 4 results.