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 14 results. Next

A384821 G.f. A(x) satisfies -1/x = Sum_{n=-oo..+oo} A(x)^n * x^n * (1 - x^n)^(n+2).

Original entry on oeis.org

1, 2, 5, 22, 91, 416, 1978, 9738, 49181, 253572, 1328528, 7053672, 37866294, 205188765, 1120824743, 6165155890, 34119043994, 189839648588, 1061344406923, 5959197795092, 33588952625106, 189986944364176, 1078034452020854, 6134848540680166, 35005230073846833, 200229444332667654
Offset: 0

Views

Author

Paul D. Hanna, Jun 10 2025

Keywords

Examples

			G.f.: A(x) = 1 + 2*x + 5*x^2 + 22*x^3 + 91*x^4 + 416*x^5 + 1978*x^6 + 9738*x^7 + 49181*x^8 + 253572*x^9 + 1328528*x^10 + ...
SPECIFIC VALUES.
A(t) = 2 at t = 0.162924020448782314256916956456618618555937137963260...
A(t) = 9/5 at t = 0.15713093477961462528780113190237390843002535981643...
A(t) = 8/5 at t = 0.14467881602482935797425598908263109752382579929421...
A(t) = 3/2 at t = 0.13461615563760120581581313629107981605312435881819...
A(t) = 4/3 at t = 0.10915621052082212882653574706851509193398803739915...
A(1/7) = 1.5793911503434252677981671019480264164820055324466...
A(1/8) = 1.4268350851974567615394958810072981944850896947894...
A(1/9) = 1.3435470274993477728207146854713823085043981519155...
A(1/10) = 1.2892440747830023480637465318368592024118039394009...
A(1/11) = 1.2505209808081799972669805855553805055082827658365...
		

Crossrefs

Programs

  • PARI
    {a(n) = my(A=[1,2,0]); for(i=1, n, A = concat(A, 0);
    A[#A-1] = polcoeff( sum(m=-#A, #A, x^m * Ser(A)^m * (1 - x^m +x*O(x^n))^(m+2) ), #A-4)); 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 formulas.
(1) -1/x = Sum_{n=-oo..+oo} A(x)^n * x^n * (1 - x^n)^(n+2).
(2) -x = Sum_{n=-oo..+oo, n<>0} (-1/A(x))^n * x^((n-1)*(n-2)) / (1 - x^n)^(n-2).
a(n) ~ c * d^n / n^(3/2), where d = 6.07021478936467894926862346663483720359... and c = 0.6881950589132830412100382237325446... - Vaclav Kotesovec, Jun 11 2025

A384822 G.f. A(x) satisfies 1/x^5 = Sum_{n=-oo..+oo} A(x)^n * x^n * (1 - x^n)^(n+4).

Original entry on oeis.org

1, 1, 5, 19, 109, 598, 3592, 22110, 140467, 911136, 6014277, 40260501, 272682397, 1865181921, 12866239311, 89403333632, 625211046931, 4396844409898, 31075863324446, 220618909826500, 1572549447431889, 11249693613964519, 80743512234554655, 581272589032594530, 4196118995069449989
Offset: 0

Views

Author

Paul D. Hanna, Jun 10 2025

Keywords

Examples

			G.f.: A(x) = 1 + x + 5*x^2 + 19*x^3 + 109*x^4 + 598*x^5 + 3592*x^6 + 22110*x^7 + 140467*x^8 + 911136*x^9 + 6014277*x^10 + ...
		

Crossrefs

Programs

  • PARI
    {a(n) = my(A=[1,1,0,0]); for(i=1, n, A = concat(A, 0);
    A[#A-2] = -polcoeff( sum(m=-#A, #A, x^m * Ser(A)^m * (1 - x^m +x*O(x^n))^(m+4) ), #A-9)); 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 formulas.
(1) 1/x^5 = Sum_{n=-oo..+oo} A(x)^n * x^n * (1 - x^n)^(n+4).
(2) x = Sum_{n=-oo..+oo, n<>0} (-1/A(x))^n * x^((n-2)*(n-3)) / (1 - x^n)^(n-4).
a(n) ~ c * d^n / n^(3/2), where d = 7.687452504111926947946743863677977... and c = 0.2779337748307189293421456249838... - Vaclav Kotesovec, Jun 11 2025

A384823 G.f. A(x) satisfies -1/x^11 = Sum_{n=-oo..+oo} A(x)^n * x^n * (1 - x^n)^(n+6).

Original entry on oeis.org

1, 1, 4, 28, 173, 1262, 9593, 75928, 618342, 5149640, 43650123, 375347585, 3266282211, 28709930633, 254526671024, 2273271614848, 20435110855838, 184745786960642, 1678668998195885, 15321962225034079, 140418372363945954, 1291587696225346583, 11919771215919819476, 110338977972166474055
Offset: 0

Views

Author

Paul D. Hanna, Jun 10 2025

Keywords

Examples

			G.f.: A(x) = 1 + x + 4*x^2 + 28*x^3 + 173*x^4 + 1262*x^5 + 9593*x^6 + 75928*x^7 + 618342*x^8 + 5149640*x^9 + 43650123*x^10 + ...
		

Crossrefs

Programs

  • PARI
    {a(n) = my(A=[1,1,0,0,0]); for(i=1, n, A = concat(A, 0);
    A[#A-3] = polcoeff( sum(m=-#A, #A, x^m * Ser(A)^m * (1 - x^m +x*O(x^n))^(m+6) ), #A-16)); 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 formulas.
(1) -1/x^11 = Sum_{n=-oo..+oo} A(x)^n * x^n * (1 - x^n)^(n+6).
(2) -x = Sum_{n=-oo..+oo, n<>0} (-1/A(x))^n * x^((n-3)*(n-4)) / (1 - x^n)^(n-6).
a(n) ~ c * d^n / n^(3/2), where d = 9.887717015668710733345454711929087306... and c = 0.160435430066288197856237263106693... - Vaclav Kotesovec, Jun 11 2025

A384824 G.f. A(x) satisfies 1/x^19 = Sum_{n=-oo..+oo} A(x)^n * x^n * (1 - x^n)^(n+8).

Original entry on oeis.org

1, 1, 5, 38, 319, 2871, 27507, 273925, 2808973, 29457644, 314470771, 3405995019, 37334767867, 413397265017, 4617060957512, 51951448775027, 588371324004508, 6701761863368579, 76723673176823126, 882342098781937683, 10188542630975395255, 118082022786322630334, 1373108879790849494070
Offset: 0

Views

Author

Paul D. Hanna, Jun 10 2025

Keywords

Examples

			G.f.: A(x) = 1 + x + 5*x^2 + 38*x^3 + 319*x^4 + 2871*x^5 + 27507*x^6 + 273925*x^7 + 2808973*x^8 + 29457644*x^9 + 314470771*x^10 + ...
		

Crossrefs

Programs

  • PARI
    {a(n) = my(A=[1,1,0,0,0,0]); for(i=1, n, A = concat(A, 0);
    A[#A-4] = -polcoeff( sum(m=-#A, #A, x^m * Ser(A)^m * (1 - x^m +x*O(x^n))^(m+8) ), #A-25)); 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 formulas.
(1) 1/x^19 = Sum_{n=-oo..+oo} A(x)^n * x^n * (1 - x^n)^(n+8).
(2) x = Sum_{n=-oo..+oo, n<>0} (-1/A(x))^n * x^((n-4)*(n-5)) / (1 - x^n)^(n-8).
a(n) ~ c * d^n / n^(3/2), where d = 12.46033620173328231233579215988893957838459959... and c = 0.113752375605091798753361983956448030623... - Vaclav Kotesovec, Jun 11 2025

A384825 G.f. A(x) satisfies -1/x^29 = Sum_{n=-oo..+oo} A(x)^n * x^n * (1 - x^n)^(n+10).

Original entry on oeis.org

1, 1, 6, 54, 542, 5955, 69114, 835140, 10391843, 132262619, 1713785727, 22531557603, 299817809184, 4030217936308, 54646151953660, 746513545616000, 10264746883787021, 141955200254335604, 1973170863256461516, 27551902179444882489, 386288077655575999571, 5435910477286670671340
Offset: 0

Views

Author

Paul D. Hanna, Jun 10 2025

Keywords

Examples

			G.f.: A(x) = 1 + x + 6*x^2 + 54*x^3 + 542*x^4 + 5955*x^5 + 69114*x^6 + 835140*x^7 + 10391843*x^8 + 132262619*x^9 + 1713785727*x^10 + ...
		

Crossrefs

Programs

  • PARI
    {a(n) = my(A=[1,1,0,0,0,0,0]); for(i=1, n, A = concat(A, 0);
    A[#A-5] = polcoeff( sum(m=-#A, #A, x^m * Ser(A)^m * (1 - x^m +x*O(x^n))^(m+10) ), #A-36)); 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 formulas.
(1) -1/x^29 = Sum_{n=-oo..+oo} A(x)^n * x^n * (1 - x^n)^(n+10).
(2) -x = Sum_{n=-oo..+oo, n<>0} (-1/A(x))^n * x^((n-5)*(n-6)) / (1 - x^n)^(n-10).
a(n) ~ c * d^n / n^(3/2), where d = 15.130878695250901787504105640277512076291321821... and c = 0.088532592960846902874974330489987793829057... - Vaclav Kotesovec, Jun 11 2025

A384826 G.f. A(x) satisfies 1/x^41 = Sum_{n=-oo..+oo} A(x)^n * x^n * (1 - x^n)^(n+12).

Original entry on oeis.org

1, 1, 7, 73, 861, 11112, 151828, 2159179, 31627690, 473917665, 7230164079, 111926802631, 1753762735460, 27760507986844, 443257137593369, 7130838718144623, 115469073853104486, 1880570694656739472, 30784302913287253256, 506228988080918570208, 8358750672258509735440, 138528877561300962357350
Offset: 0

Views

Author

Paul D. Hanna, Jun 10 2025

Keywords

Examples

			G.f.: A(x) = 1 + x + 7*x^2 + 73*x^3 + 861*x^4 + 11112*x^5 + 151828*x^6 + 2159179*x^7 + 31627690*x^8 + 473917665*x^9 + 7230164079*x^10 + ...
		

Crossrefs

Programs

  • PARI
    {a(n) = my(A=[1,1,0,0,0,0,0,0]); for(i=1, n, A = concat(A, 0);
    A[#A-6] = -polcoeff( sum(m=-#A, #A, x^m * Ser(A)^m * (1 - x^m +x*O(x^n))^(m+12) ), #A-49)); 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 formulas.
(1) 1/x^41 = Sum_{n=-oo..+oo} A(x)^n * x^n * (1 - x^n)^(n+12).
(2) x = Sum_{n=-oo..+oo, n<>0} (-1/A(x))^n * x^((n-6)*(n-7)) / (1 - x^n)^(n-12).
a(n) ~ c * d^n / n^(3/2), where d = 17.821078213117779013059276484226766696509894506... and c = 0.072486824411461280676499747682168909434267... - Vaclav Kotesovec, Jun 11 2025

A384827 G.f. A(x) satisfies -1/x^55 = Sum_{n=-oo..+oo} A(x)^n * x^n * (1 - x^n)^(n+14).

Original entry on oeis.org

1, 1, 8, 95, 1288, 19116, 300511, 4918268, 82918049, 1430142380, 25115651237, 447578072658, 8073426806649, 147122009148252, 2704441907759235, 50088849266618466, 933792151007378231, 17509062834076661230, 329985690688947517626, 6247533413700369107192, 118768564127167799819733
Offset: 0

Views

Author

Paul D. Hanna, Jun 10 2025

Keywords

Examples

			G.f.: A(x) = 1 + x + 8*x^2 + 95*x^3 + 1288*x^4 + 19116*x^5 + 300511*x^6 + 4918268*x^7 + 82918049*x^8 + 1430142380*x^9 + 25115651237*x^10 + ...
		

Crossrefs

Programs

  • PARI
    {a(n) = my(A=[1,1,0,0,0,0,0,0,0]); for(i=1, n, A = concat(A, 0);
    A[#A-7] = polcoeff( sum(m=-#A, #A, x^m * Ser(A)^m * (1 - x^m +x*O(x^n))^(m+14) ), #A-64)); 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 formulas.
(1) -1/x^55 = Sum_{n=-oo..+oo} A(x)^n * x^n * (1 - x^n)^(n+14).
(2) -x = Sum_{n=-oo..+oo, n<>0} (-1/A(x))^n * x^((n-7)*(n-8)) / (1 - x^n)^(n-14).
a(n) ~ c * d^n / n^(3/2), where d = 20.5190724870235230419993391970202418416256614273528... and c = 0.06135641554365612129872100433075021800206923942... - Vaclav Kotesovec, Jun 11 2025

A384828 G.f. A(x) satisfies 1/x^71 = Sum_{n=-oo..+oo} A(x)^n * x^n * (1 - x^n)^(n+16).

Original entry on oeis.org

1, 1, 9, 120, 1839, 30862, 548783, 10160786, 193811734, 3782270289, 75158649892, 1515578476370, 30935212293083, 637920390487505, 13269865608471203, 278121828806207328, 5867506406619195047, 124502776024601555996, 2655381364988431518262, 56892952987400631546208, 1223972213493916563960331
Offset: 0

Views

Author

Paul D. Hanna, Jun 10 2025

Keywords

Examples

			G.f.: A(x) = 1 + x + 9*x^2 + 120*x^3 + 1839*x^4 + 30862*x^5 + 548783*x^6 + 10160786*x^7 + 193811734*x^8 + 3782270289*x^9 + 75158649892*x^10 + ...
		

Crossrefs

Programs

  • PARI
    {a(n) = my(A=[1,1,0,0,0,0,0,0,0,0]); for(i=1, n, A = concat(A, 0);
    A[#A-8] = -polcoeff( sum(m=-#A, #A, x^m * Ser(A)^m * (1 - x^m +x*O(x^n))^(m+16) ), #A-81)); 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 formulas.
(1) 1/x^71 = Sum_{n=-oo..+oo} A(x)^n * x^n * (1 - x^n)^(n+16).
(2) x = Sum_{n=-oo..+oo, n<>0} (-1/A(x))^n * x^((n-8)*(n-9)) / (1 - x^n)^(n-16).
a(n) ~ c * d^n / n^(3/2), where d = 23.2218466497883684132359544378917382382303363986... and c = 0.05318473987345007866210446949223464954972731... - Vaclav Kotesovec, Jun 11 2025

A366730 Expansion of g.f. A(x,y) satisfying 0 = Sum_{n=-oo..+oo} x^n * A(x,y)^n * (y - x^(n-1))^(n+1), as a triangle of coefficients T(n,k) of x^n*y^k in A(x,y), read by rows n >= 0.

Original entry on oeis.org

1, 0, 1, 0, -2, 2, 0, 3, -6, 5, 0, -6, 14, -20, 14, 0, 11, -36, 59, -70, 42, 0, -18, 87, -176, 246, -252, 132, 0, 28, -190, 500, -824, 1022, -924, 429, 0, -44, 386, -1312, 2615, -3780, 4236, -3432, 1430, 0, 69, -756, 3218, -7734, 13107, -17112, 17523, -12870, 4862, 0, -104, 1443, -7514, 21496, -42444, 64031, -76692, 72358, -48620, 16796
Offset: 0

Views

Author

Paul D. Hanna, Oct 29 2023

Keywords

Examples

			G.f.: A(x,y) = 1 + x*y + x^2*(-2*y + 2*y^2) + x^3*(3*y - 6*y^2 + 5*y^3) + x^4*(-6*y + 14*y^2 - 20*y^3 + 14*y^4) + x^5*(11*y - 36*y^2 + 59*y^3 - 70*y^4 + 42*y^5) + x^6*(-18*y + 87*y^2 - 176*y^3 + 246*y^4 - 252*y^5 + 132*y^6) + x^7*(28*y - 190*y^2 + 500*y^3 - 824*y^4 + 1022*y^5 - 924*y^6 + 429*y^7) + x^8*(-44*y + 386*y^2 - 1312*y^3 + 2615*y^4 - 3780*y^5 + 4236*y^6 - 3432*y^7 + 1430*y^8) + x^9*(69*y - 756*y^2 + 3218*y^3 - 7734*y^4 + 13107*y^5 - 17112*y^6 + 17523*y^7 - 12870*y^8 + 4862*y^9) + ...
where A = A(x,y) satisfies
0 = Sum_{n=-oo..+oo} x^n * A^n * (y - x^(n-1))^(n+1);
explicitly,
0 = ((-A + 1)/A)/x + y + (A*y^2 - 2*A*y + ((A^3 - 1)/A^2))*x + A^2*y^3*x^2 + (A^3*y^4 - 3*A^2*y^2)*x^3 + (A^4*y^5 + ((3*A^4 - 1)/A^2)*y)*x^4 + (A^5*y^6 - 4*A^3*y^3 + ((-A^5 + 1)/A^3))*x^5 + A^6*y^7*x^6 + (A^7*y^8 - 5*A^4*y^4 + ((6*A^5 - 1)/A^2)*y^2)*x^7 + A^8*y^9*x^8 + (A^9*y^10 - 6*A^5*y^5 + ((-4*A^6 + 2)/A^3)*y)*x^9 + (A^10*y^11 + ((10*A^6 - 1)/A^2)*y^3)*x^10 + ...
This triangle of coefficients of x^n*y^k in A(x,y) begins:
1;
0, 1;
0, -2, 2;
0, 3, -6, 5;
0, -6, 14, -20, 14;
0, 11, -36, 59, -70, 42;
0, -18, 87, -176, 246, -252, 132;
0, 28, -190, 500, -824, 1022, -924, 429;
0, -44, 386, -1312, 2615, -3780, 4236, -3432, 1430;
0, 69, -756, 3218, -7734, 13107, -17112, 17523, -12870, 4862;
0, -104, 1443, -7514, 21496, -42444, 64031, -76692, 72358, -48620, 16796;
0, 152, -2668, 16862, -56856, 129425, -223458, 307189, -340912, 298298, -184756, 58786;
0, -222, 4782, -36456, 144159, -375618, 734310, -1143924, 1453221, -1504932, 1227876, -705432, 208012; ...
in which the main diagonal equals the Catalan numbers (A000108), and column 1 equals the coefficients in Product_{n>=1} (1 - q^(2*n-1))^2/(1 - q^(2*n))^2 (A274621).
		

Crossrefs

Cf. A274621 (column 1), A000108 (diagonal), A366736 (central terms).
Cf. A366731 (y=1), A366732 (y=2), A366733 (y=3), A366734 (y=4), A366735 (y=-1).

Programs

  • PARI
    {T(n,k) = my(A=[1]); for(i=1,n, A = concat(A,0);
    A[#A] = polcoeff( sum(n=-#A,#A, x^n * Ser(A)^n * (y - x^(n-1))^(n+1) ), #A-2)); polcoeff(A[n+1],k)}
    for(n=0,12, for(k=0,n, print1(T(n,k),", "));print(""))

Formula

G.f. A(x,y) = Sum_{n>=0} sum_{k=0..n} T(n,k)*x^n*y^k satisfies the following formulas.
(1) 0 = Sum_{n=-oo..+oo} x^n * A(x,y)^n * (y - x^(n-1))^(n+1).
(2) 0 = Sum_{n=-oo..+oo} (-1)^n * x^(n*(n-1)) / ( A(x,y)^n * (1 - y*x^(n+1))^(n-1) ).

A366732 Expansion of g.f. A(x) satisfying 0 = Sum_{n=-oo..+oo} x^n * A(x)^n * (2 - x^(n-1))^(n+1).

Original entry on oeis.org

1, 2, 4, 22, 108, 574, 3224, 18592, 109728, 660938, 4041900, 25034000, 156724204, 990127086, 6304425800, 40416596578, 260658078580, 1689976752116, 11008752656960, 72016455973262, 472912945955364, 3116243639293972, 20599091568973324, 136557058462319178, 907668022344460584
Offset: 0

Views

Author

Paul D. Hanna, Oct 29 2023

Keywords

Comments

a(n) = Sum_{k=0..n} A366730(n,k) * 2^k for n >= 0.

Examples

			G.f.: A(x) = 1 + 2*x + 4*x^2 + 22*x^3 + 108*x^4 + 574*x^5 + 3224*x^6 + 18592*x^7 + 109728*x^8 + 660938*x^9 + 4041900*x^10 + 25034000*x^11 + ...
		

Crossrefs

Programs

  • PARI
    {a(n) = my(A=[1]); for(i=1,n, A = concat(A,0);
    A[#A] = polcoeff( sum(n=-#A,#A, x^n * Ser(A)^n * (2 - x^(n-1))^(n+1) ), #A-2));A[n+1]}
    for(n=0,40,print1(a(n),", "))

Formula

G.f. A(x) = Sum_{n>=0} a(n)*x^n satisfies the following formulas.
(1) 0 = Sum_{n=-oo..+oo} x^n * A(x)^n * (2 - x^(n-1))^(n+1).
(2) 0 = Sum_{n=-oo..+oo} (-1)^n * x^(n*(n-1)) / ( A(x)^n * (1 - 2*x^(n+1))^(n-1) ).
Showing 1-10 of 14 results. Next