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 1-10 of 11 results. Next

A363310 Expansion of g.f. A(x) satisfying A(x) = 1 + x*G(x)^5, where G(x) = 1 + x*(G(x)^3 + G(x)^5) is the g.f. of A363311.

Original entry on oeis.org

1, 1, 10, 120, 1620, 23560, 360352, 5714800, 93129840, 1550132320, 26242225600, 450448137216, 7821608426880, 137145465358080, 2424899712359680, 43186456105340160, 774013543036174080, 13949937641606981120, 252666943472167541760, 4596736161565468815360
Offset: 0

Views

Author

Paul D. Hanna, May 29 2023

Keywords

Examples

			G.f.: A(x) =  = 1 + x + 10*x^2 + 120*x^3 + 1620*x^4 + 23560*x^5 + 360352*x^6 + 5714800*x^7 + 93129840*x^8 + 1550132320*x^9 + 26242225600*x^10 + ...
such that A(x) = 1 + x*G(x)^5 where
G(x) = 1 + 2*x + 16*x^2 + 180*x^3 + 2360*x^4 + 33760*x^5 + 510928*x^6 + 8043440*x^7 + ... + A363311(n)*x^n + ...
satisfies G(x) = 1 + x*(G(x)^3 + G(x)^5).
Also, A(x) = B(x*A(x)^2) where B(x) = A(x/B(x)^2) begins
B(x) = 1 + x + 8*x^2 + 67*x^3 + 590*x^4 + 5403*x^5 + 51034*x^6 + 494268*x^7 + ... + A363309(n)*x^n + ...
		

Crossrefs

Programs

  • PARI
    {a(n) = if(n==0,1, sum(k=0, n-1, 5*binomial(n-1, k)*binomial(3*n+2*k+2, n-1)/(3*n+2*k+2) ) )}
    for(n=0, 20, print1(a(n), ", "))

Formula

G.f. A(x) = Sum_{n>=0} a(n)*x^n may be defined as follows; here, B(x) is the g.f. of A363309 and F(x) is the g.f. of A001764.
(1) A(x) = 1 + x*G(x)^5, where G(x) = 1 + x*(G(x)^3 + G(x)^5) is the g.f. of A363311.
(2) A(x) = B(x*A(x)^2) where B(x) = F(x*F(x)^5) and F(x) = 1 + x*F(x)^3.
(3) A(x) = sqrt( (1/x)*Series_Reversion( x/B(x)^2 ) ), where B(x) is the g.f. of A363309.
(4) a(n) = Sum_{k=0..n-1} 5*binomial(n-1, k)*binomial(3*n+2*k+2, n-1)/(3*n+2*k+2) for n > 1 with a(0) = 1.

A363304 Expansion of g.f. A(x) satisfying A(x) = 1 + x*(A(x)^4 + A(x)^7).

Original entry on oeis.org

1, 2, 22, 350, 6538, 133658, 2895214, 65294502, 1516963346, 36056007602, 872615973766, 21430572885422, 532737957899290, 13379121740808266, 338941379999841758, 8651415618928816886, 222278432539991439906, 5743974149517874477922, 149192980850883703986166
Offset: 0

Views

Author

Paul D. Hanna, May 29 2023

Keywords

Examples

			G.f.: A(x) = 1 + 2*x + 22*x^2 + 350*x^3 + 6538*x^4 + 133658*x^5 + 2895214*x^6 + 65294502*x^7 + 1516963346*x^8 + 36056007602*x^9 + ...
where A(x) = 1 + x*(A(x)^4 + A(x)^7).
RELATED SERIES.
A(x)^4 = 1 + 8*x + 112*x^2 + 1960*x^3 + 38528*x^4 + 813064*x^5 + 17998512*x^6 + 412364968*x^7 + ...
A(x)^7 = 1 + 14*x + 238*x^2 + 4578*x^3 + 95130*x^4 + 2082150*x^5 + 47295990*x^6 + 1104598378*x^7 + ...
		

Crossrefs

Programs

  • PARI
    {a(n) = sum(k=0, n, binomial(n, k)*binomial(4*n+3*k+1, n)/(4*n+3*k+1) )}
    for(n=0, 20, print1(a(n), ", "))

Formula

G.f.: A(x) = Sum_{n>=0} a(n)*x^n may be defined by the following.
(1) A(x) = 1 + x*(A(x)^4 + A(x)^7).
(2) a(n) = Sum_{k=0..n} binomial(n, k)*binomial(4*n+3*k+1, n)/(4*n+3*k+1) for n >= 0.

A363309 Expansion of g.f. A(x) = F(x*F(x)^5), where F(x) = 1 + x*F(x)^3 is the g.f. of A001764.

Original entry on oeis.org

1, 1, 8, 67, 590, 5403, 51034, 494268, 4886794, 49153835, 501631980, 5182767291, 54115252508, 570206217940, 6055948422280, 64765311313944, 696876526961130, 7539151412082315, 81957518070961472, 894826829565106185, 9808173152466891270, 107888887505651377475
Offset: 0

Views

Author

Paul D. Hanna, May 29 2023

Keywords

Comments

Compare the g.f. A(x) = F(x*F(x)^5) to F(-x*F(x)^5) = 1/F(x), where F(x) = 1 + x*F(x)^3 is the g.f. of A001764.
Conjecture: given A(x) = F(x*F(x)^(2*n-1)) where F(x) = 1 + x*F(x)^n, let B(x) = A(x*B(x)^(n-1)), then ((B(x) - 1)/x)^(1/(2*n-1)) is an integer series for n >= 1. Incidentally, the function A(x) = F(x*F(x)^(2*n-1)) is interesting because F(-x*F(x)^(2*n-1)) = 1/F(x) when F(x) = 1 + x*F(x)^n. This sequence illustrates the case for n = 3; for n = 2, see A363308.

Examples

			G.f.: A(x) = 1 + x + 8*x^2 + 67*x^3 + 590*x^4 + 5403*x^5 + 51034*x^6 + 494268*x^7 + 4886794*x^8 + 49153835*x^9 + 501631980*x^10 + ...
such that A(x) = F(x*F(x)^5) where F(x) = 1 + x*F(x)^3 begins
F(x) = 1 + x + 3*x^2 + 12*x^3 + 55*x^4 + 273*x^5 + 1428*x^6 + 7752*x^7 + ... + A001764(n)*x^n + ...
RELATED SERIES.
Let B(x) = A(x*B(x)^2) which begins
B(x) = 1 + x + 10*x^2 + 120*x^3 + 1620*x^4 + 23560*x^5 + 360352*x^6 + 5714800*x^7 + 93129840*x^8 + ... + A363310(n)*x^n + ...
then
( (B(x) - 1)/x )^(1/5) = 1 + 2*x + 16*x^2 + 180*x^3 + 2360*x^4 + 33760*x^5 + 510928*x^6 + 8043440*x^7 + ... + A363311(n)*x^n + ...
is an integer series.
		

Crossrefs

Programs

  • PARI
    {a(n) = if(n==0, 1, sum(k=1, n, 5*k* binomial(3*k+1, k) * binomial(3*n+2*k, n-k) / ((3*k+1)*(3*n+2*k)) ) )}
    for(n=0, 30, print1(a(n), ", "))
    
  • PARI
    /* G.f. A(x) = F(x*F(x)^5), where F(x) = 1 + x*F(x)^3 */
    {a(n) = my(F = 1); for(i=1,n, F = 1 + x*F^3 + x*O(x^n));
    polcoeff( subst(F, x, x*F^5), n)}
    for(n=0, 30, print1(a(n), ", "))

Formula

G.f. A(x) = Sum_{n>=0} a(n)*x^n may be defined as follows; here, F(x) is the g.f. of A001764.
(1) A(x) = F(x*F(x)^5), where F(x) = 1 + x*F(x)^3.
(2) A(x) = B(x/A(x)^2) where B(x) = A(x*B(x)^2) = F( x*B(x)^2 * F(x*B(x)^2)^5 ) is the g.f. of A363310.
(3) a(n) = Sum_{k=1..n} 5*k* binomial(3*k+1, k) * binomial(3*n+2*k, n-k) / ((3*k+1)*(3*n+2*k)) for n > 0, with a(0) = 1.

A364167 Expansion of g.f. A(x) satisfying A(x) = 1 + x * A(x)^3 * (1 + A(x)^3).

Original entry on oeis.org

1, 2, 18, 234, 3570, 59586, 1053570, 19392490, 367677090, 7131417282, 140834140722, 2822214963882, 57243994984722, 1172991472484610, 24245748916730658, 504935751379031082, 10584721220759172162, 223163804001804187266, 4729176407109705542994, 100676187744957784842090
Offset: 0

Views

Author

Seiichi Manyama, Jul 13 2023

Keywords

Crossrefs

Programs

  • Maple
    a:= n-> sum(binomial(n, k)*binomial(3*n+3*k+1, n)/(3*n+3*k+1), k=0..n):
    seq(a(n), n=0..49); # Christian N. Hofmann, Jul 14 2023
  • PARI
    a(n) = sum(k=0, n, binomial(n, k)*binomial(3*n+3*k+1, n)/(3*n+3*k+1));

Formula

a(n) = Sum_{k=0..n} binomial(n,k) * binomial(3*n+3*k+1,n)/(3*n+3*k+1).

A364397 G.f. satisfies A(x) = 1 + x/A(x)^2*(1 + 1/A(x)^2).

Original entry on oeis.org

1, 2, -12, 124, -1560, 21776, -324256, 5046096, -81086112, 1335113408, -22408067200, 381942129792, -6593494698752, 115044039049728, -2025580621035520, 35943759448886528, -642162301086308864, 11541259115333684224, -208521418711421405184
Offset: 0

Views

Author

Seiichi Manyama, Jul 22 2023

Keywords

Crossrefs

Programs

  • PARI
    a(n) = if(n==0, 1, (-1)^(n-1)*sum(k=0, n, binomial(n, k)*binomial(3*n+2*k-2, n-1))/n);

Formula

G.f.: A(x) = 1/B(-x) where B(x) is the g.f. of A363311.
a(n) = (-1)^(n-1) * (1/n) * Sum_{k=0..n} binomial(n,k) * binomial(3*n+2*k-2,n-1) for n > 0.
a(n) ~ c*(-1)^(n+1)*27^n*4^(-n)*3F2([-n, 3*n/2, (3n-1)/2], [n, n+1/2], -1)*n^(-3/2), with c = 1/(3*sqrt(3*Pi)). - Stefano Spezia, Oct 21 2023

A371661 G.f. satisfies A(x) = 1 + x * A(x)^3 * (1 + A(x))^2.

Original entry on oeis.org

1, 4, 64, 1424, 36800, 1036160, 30843648, 954671360, 30415326208, 990831196160, 32853724512256, 1105132250898432, 37620337933582336, 1293586791397064704, 44863864476704768000, 1567543145774827241472, 55125711913212153954304
Offset: 0

Views

Author

Seiichi Manyama, Apr 01 2024

Keywords

Crossrefs

Programs

  • PARI
    a(n) = if(n==0, 1, sum(k=0, (n-1)\2, 4^(n-k)*binomial(n, k)*binomial(4*n-k, n-1-2*k))/n);

Formula

a(n) = (1/n) * Sum_{k=0..floor((n-1)/2)} 4^(n-k) * binomial(n,k) * binomial(4*n-k,n-1-2*k) for n > 0.
a(n) = 2^n * A371669(n). - Seiichi Manyama, Dec 26 2024

A363305 Expansion of g.f. A(x) satisfying A(x) = 1 + x*(A(x)^5 + A(x)^9).

Original entry on oeis.org

1, 2, 28, 576, 13968, 371280, 10465152, 307252032, 9295409664, 287758274304, 9071667965184, 290237226038272, 9399819302979584, 307570021821937664, 10152439243763290112, 337658352835320934400, 11304320019217804476416, 380650592731460987617280
Offset: 0

Views

Author

Paul D. Hanna, May 29 2023

Keywords

Examples

			G.f.: A(x) = 1 + 2*x + 28*x^2 + 576*x^3 + 13968*x^4 + 371280*x^5 + 10465152*x^6 + 307252032*x^7 + 9295409664*x^8 + ...
where A(x) = 1 + x*(A(x)^5 + A(x)^9).
RELATED SERIES.
A(x)^5 = 1 + 10*x + 180*x^2 + 4080*x^3 + 104160*x^4 + 2858352*x^5 + 82336320*x^6 + 2455727040*x^7 + ...
A(x)^9 = 1 + 18*x + 396*x^2 + 9888*x^3 + 267120*x^4 + 7606800*x^5 + 224915712*x^6 + 6839682624*x^7 + ...
		

Crossrefs

Programs

  • PARI
    {a(n) = sum(k=0, n, binomial(n, k)*binomial(5*n+4*k+1, n)/(5*n+4*k+1) )}
    for(n=0, 20, print1(a(n), ", "))

Formula

G.f.: A(x) = Sum_{n>=0} a(n)*x^n may be defined by the following.
(1) A(x) = 1 + x*(A(x)^5 + A(x)^9).
(2) a(n) = Sum_{k=0..n} binomial(n, k)*binomial(5*n+4*k+1, n)/(5*n+4*k+1) for n >= 0.

A363380 G.f. satisfies A(x) = 1 + x * A(x)^4 * (1 + A(x)^2).

Original entry on oeis.org

1, 2, 20, 284, 4712, 85392, 1638112, 32699472, 672188768, 14133399744, 302535052160, 6570819330688, 144442463464704, 3207564324825600, 71848240540852224, 1621452789508328704, 36831997860270007808, 841470878382566444032
Offset: 0

Views

Author

Seiichi Manyama, May 29 2023

Keywords

Crossrefs

Programs

  • PARI
    a(n) = sum(k=0, n, binomial(n, k)*binomial(4*n+2*k+1, n)/(4*n+2*k+1));

Formula

a(n) = Sum_{k=0..n} binomial(n,k) * binomial(4*n+2*k+1,n)/(4*n+2*k+1).

A364195 Expansion of g.f. A(x) satisfying A(x) = 1 + x * A(x)^5 * (1 + A(x)^2).

Original entry on oeis.org

1, 2, 24, 412, 8280, 181904, 4232048, 102479184, 2555884896, 65207430848, 1693785940992, 44643489969792, 1190986788639232, 32097745138518528, 872595854798515456, 23900545715576753408, 658934625866433496576, 18271554709525993556992, 509241947434834351042560
Offset: 0

Views

Author

Seiichi Manyama, Jul 13 2023

Keywords

Crossrefs

Programs

  • PARI
    a(n) = sum(k=0, n, binomial(n, k)*binomial(5*n+2*k+1, n)/(5*n+2*k+1));

Formula

a(n) = Sum_{k=0..n} binomial(n,k) * binomial(5*n+2*k+1,n)/(5*n+2*k+1).

A371660 G.f. satisfies A(x) = 1 + x * A(x)^3 * (1 + A(x) + A(x)^2).

Original entry on oeis.org

1, 3, 36, 603, 11745, 249372, 5599044, 130735620, 3142426428, 77238209502, 1932396279066, 49047725266101, 1259884849971465, 32690034127387431, 855528520866461010, 22556952666651901761, 598607836414445357145, 15976563963437863357146
Offset: 0

Views

Author

Seiichi Manyama, Apr 01 2024

Keywords

Crossrefs

Programs

  • PARI
    a(n) = if(n==0, 1, sum(k=0, (n-1)\2, 3^(n-k)*binomial(n, k)*binomial(4*n-k, n-1-2*k))/n);

Formula

a(n) = (1/n) * Sum_{k=0..floor((n-1)/2)} 3^(n-k) * binomial(n,k) * binomial(4*n-k,n-1-2*k) for n > 0.
Showing 1-10 of 11 results. Next