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.

Previous Showing 11-20 of 20 results.

A301585 G.f.: Sum_{n>=0} ((1+x)^(3*n) - 1)^n.

Original entry on oeis.org

1, 3, 39, 910, 29949, 1271751, 66116065, 4066082856, 288701376912, 23240635243591, 2091554595246705, 208085119389952134, 22676957610808295192, 2686515300821612112411, 343760257348413122290260, 47248346582443326267328400, 6942339982115290619799947901, 1085919469129099832397573088863, 180160797497273341662653292624309, 31598815412054398239059538582525618
Offset: 0

Views

Author

Paul D. Hanna, Mar 24 2018

Keywords

Examples

			G.f.: A(x) = 1 + 3*x + 39*x^2 + 910*x^3 + 29949*x^4 + 1271751*x^5 + 66116065*x^6 + 4066082856*x^7 + 288701376912*x^8 + ...
such that
A(x) = 1 + ((1+x)^3-1) + ((1+x)^6-1)^2 + ((1+x)^9-1)^3 + ((1+x)^12-1)^4 + ((1+x)^15-1)^5 + ((1+x)^18-1)^6 + ((1+x)^21-1)^7 + ...
Also,
A(x) = 1/2 + (1+x)^3/(1 + (1+x)^3)^2 + (1+x)^12/(1 + (1+x)^6)^3 + (1+x)^27/(1 + (1+x)^9)^4 + (1+x)^48/(1 + (1+x)^12)^5 + (1+x)^75/(1 + (1+x)^15)^6 + ...
		

Crossrefs

Programs

  • PARI
    {a(n) = my(A,o=x*O(x^n)); A = sum(m=0,n, ((1+x +o)^(3*m) - 1)^m ); polcoeff(A,n)}
    for(n=0,30,print1(a(n),", "))

Formula

G.f.: Sum_{n>=0} (1+x)^(3*n^2) /(1 + (1+x)^(3*n))^(n+1).
a(n) ~ c * d^n * n! / sqrt(n), where d = 3*A317855 = 9.4832659615962864414905166077643974751791483225656690248818346226130911776579... and c = 0.3108017465925995208675813879173750641359609... - Vaclav Kotesovec, Aug 09 2018

A301586 G.f.: Sum_{n>=0} ((1+x)^(4*n) - 1)^n.

Original entry on oeis.org

1, 4, 70, 2180, 95729, 5422192, 375951144, 30833206304, 2919367902648, 313380517364324, 37606931999739230, 4988933437333555060, 724960700435104219679, 114519163835687116024256, 19538926882901715534673728, 3580844611314789257667535968, 701546780854024941112271649610, 146318317830136401429653726419700, 32367591848747955557013839920695374, 7569528177000020896435962191564396740
Offset: 0

Views

Author

Paul D. Hanna, Mar 24 2018

Keywords

Examples

			G.f.: A(x) = 1 + 4*x + 70*x^2 + 2180*x^3 + 95729*x^4 + 5422192*x^5 + 375951144*x^6 + 30833206304*x^7 + ...
such that
A(x) = 1 + ((1+x)^4-1) + ((1+x)^8-1)^2 + ((1+x)^12-1)^3 + ((1+x)^16-1)^4 + ((1+x)^20-1)^5 + ((1+x)^24-1)^6 + ((1+x)^28-1)^7 + ...
Also,
A(x) = 1/2 + (1+x)^4/(1 + (1+x)^4)^2 + (1+x)^16/(1 + (1+x)^8)^3 + (1+x)^36/(1 + (1+x)^12)^4 + (1+x)^64/(1 + (1+x)^16)^5 + (1+x)^100/(1 + (1+x)^20)^6 + ...
		

Crossrefs

Programs

  • PARI
    {a(n) = my(A,o=x*O(x^n)); A = sum(m=0,n, ((1+x +o)^(4*m) - 1)^m ); polcoeff(A,n)}
    for(n=0,30,print1(a(n),", "))

Formula

G.f.: Sum_{n>=0} (1+x)^(4*n^2) /(1 + (1+x)^(4*n))^(n+1).
a(n) ~ c * d^n * n! / sqrt(n), where d = 4*A317855 = 12.64435461546171525532068881035252996690553109675422536650911283015078823687... and c = 0.31492557816516652573983016205911709623053... - Vaclav Kotesovec, Aug 09 2018

A304642 G.f. A(x) satisfies: 1 = Sum_{n>=0} ( (1+x)^(n+1) - A(x) )^n.

Original entry on oeis.org

1, 2, 2, 10, 112, 1670, 30682, 663606, 16443254, 458349374, 14184612446, 482476888374, 17892738705864, 718662489646314, 31085968593760190, 1441017859748316954, 71281146361450601326, 3748236082140499881942, 208808936226479892694126, 12286084218797404915838902, 761413942238514103243322732, 49577303456014047226843229946, 3383829651598944830489407813422
Offset: 0

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Author

Paul D. Hanna, May 16 2018

Keywords

Examples

			G.f.: A(x) = 1 + 2*x + 2*x^2 + 10*x^3 + 112*x^4 + 1670*x^5 + 30682*x^6 + 663606*x^7 + 16443254*x^8 + 458349374*x^9 + 14184612446*x^10 + 482476888374*x^11 + ...
such that
1 = 1  +  ((1+x)^2 - A(x))  +  ((1+x)^3 - A(x))^2  +  ((1+x)^4 - A(x))^3  +  ((1+x)^5 - A(x))^4  +  ((1+x)^6 - A(x))^5  +  ((1+x)^7 - A(x))^6  +  ((1+x)^8 - A(x))^7 + ...
Also,
1 = 1/(1 + A(x))  +  (1+x)^2/(1 + (1+x)*A(x))^2  +  (1+x)^6/(1 + (1+x)^2*A(x))^3  +  (1+x)^12/(1 + (1+x)^3*A(x))^4  +  (1+x)^20/(1 + (1+x)^4*A(x))^5  +  (1+x)^30/(1 + (1+x)^5*A(x))^6  +  (1+x)^42/(1 + (1+x)^6*A(x))^7 + ...
		

Crossrefs

Programs

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

Formula

G.f. A(x) satisfies:
(1) 1 = Sum_{n>=0} ((1+x)^(n+1) - A(x))^n.
(2) 1 = Sum_{n>=0} (1+x)^(n*(n+1)) / (1 + (1+x)^n*A(x))^(n+1).
a(n) ~ c * d^n * n! / sqrt(n), where d = A317855 = 3.16108865386542881383... and c = 0.154769618099522133628... - Vaclav Kotesovec, Oct 14 2020

A227619 G.f.: A(x) = 1+x + Sum_{n>=2} (A(x)^n - 1)^n.

Original entry on oeis.org

1, 1, 4, 63, 1278, 29764, 758065, 20611793, 590579518, 17707907024, 553879330720, 18066513887790, 615744470668778, 22014659625607877, 830262409494773896, 33243718957578687811, 1422095813097928147636, 65311403344808947050730, 3227884786251446164710376
Offset: 0

Views

Author

Paul D. Hanna, Aug 21 2013

Keywords

Examples

			G.f.: A(x) = 1 + x + 4*x^2 + 63*x^3 + 1278*x^4 + 29764*x^5 +...
where
A(x) = 1+x + (A(x)^2 - 1)^2 + (A(x)^3 - 1)^3 + (A(x)^4 - 1)^4 + (A(x)^5 - 1)^5 +...
		

Crossrefs

Cf. A122400.

Programs

  • PARI
    {a(n)=local(A=1+x);for(i=1,n,A=1+x+sum(k=2,n,(A^k-1 +x*O(x^n))^k));polcoeff(A,n)}
    for(n=0,20,print1(a(n),", "))

Formula

a(n) ~ c * d^n * n! / sqrt(n), where d = A317855 = (1+exp(1/r))*r^2 = 3.161088653865428813830172202588132491726382774188556341627278..., r = 0.8737024332396683304965683047207192982139922672025395099... is the root of the equation exp(1/r)/r + (1+exp(1/r))*LambertW(-exp(-1/r)/r) = 0, and c = 0.9913753087... . - Vaclav Kotesovec, May 07 2014

A303057 G.f. A(x) satisfies: A(x) = Sum_{n>=0} ((1+x)^n - 1)^n / A(x)^n.

Original entry on oeis.org

1, 1, 3, 21, 221, 3117, 54597, 1136127, 27293715, 742143113, 22512196673, 753402861159, 27571631761077, 1095346704175755, 46948527167219957, 2159638211148320085, 106129271000784614099, 5549226963359699829711, 307623817602110038648839, 18022345501064909362595723, 1112657716434830018636702797
Offset: 0

Views

Author

Paul D. Hanna, Apr 20 2018

Keywords

Examples

			G.f.: A(x) = 1 + x + 3*x^2 + 21*x^3 + 221*x^4 + 3117*x^5 + 54597*x^6 + 1136127*x^7 + 27293715*x^8 + 742143113*x^9 + 22512196673*x^10 + ...
such that
A(x) = 1 + ((1+x)-1)/A(x) + ((1+x)^2-1)^2/A(x)^2 + ((1+x)^3-1)^3/A(x)^3 + ((1+x)^4-1)^4/A(x)^4 + ((1+x)^5-1)^5/A(x)^5 + ((1+x)^6-1)^6/A(x)^6 + ...
also,
1 = 1/(A(x) + 1) + (1+x)/(A(x) + (1+x))^2 + (1+x)^4/(A(x) + (1+x)^2)^3 + (1+x)^9/(A(x) + (1+x)^3)^4 + (1+x)^16/(A(x) + (1+x)^4)^5 + (1+x)^25/(A(x) + (1+x)^5)^6 + (1+x)^36/(A(x) + (1+x)^6)^7 + ... + (1+x)^(n^2) / (A(x) + (1+x)^n)^(n+1) + ...
		

Crossrefs

Cf. A303058.

Programs

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

Formula

G.f. A(x) satisfies:
(1) 1 = Sum_{n>=0} ((1+x)^n - 1)^n / A(x)^(n+1).
(2) 1 = Sum_{n>=0} (1+x)^(n^2) / (A(x) + (1+x)^n)^(n+1). - Paul D. Hanna, Dec 13 2018
a(n) ~ c * d^n * n! / sqrt(n), where d = A317855 = 3.16108865386542881383... and c = 0.212154215724410476311... - Vaclav Kotesovec, Oct 06 2020

A121886 a(n) = (1/n!)* Sum_{k=0..n} |Stirling1(n,k)|*A122399(k).

Original entry on oeis.org

1, 1, 5, 40, 444, 6324, 110023, 2261576, 53632424, 1441341350, 43290170494, 1437020742408, 52243864528990, 2064488610832106, 88106523694973953, 4038627301344466648, 197888243609535940091, 10321811633042512528240
Offset: 0

Views

Author

Vladeta Jovovic, Aug 31 2006

Keywords

Comments

Number of square matrices with nonnegative integer entries and without zero rows such that sum of all entries is equal to n. - Vladeta Jovovic, Mar 04 2008

Examples

			G.f.: A(x) = 1 + x + 5*x^2 + 40*x^3 + 444*x^4 + 6324*x^5 +...
where
A(x) = 1 + (1/(1-x) - 1) + (1/(1-x)^2 - 1)^2 + (1/(1-x)^3 - 1)^3 + ...
Also,
A(x) = 1/2 + (1-x)/(1 + (1-x))^2 + (1-x)^2/(1 + (1-x)^2)^3 +  + (1-x)^3/(1 + (1-x)^3)^4 + (1-x)^4/(1 + (1-x)^4)^5 + ...
		

Crossrefs

Programs

  • Mathematica
    Flatten[{1,Table[1/n!* Sum[Abs[StirlingS1[n,k]]*Sum[m^k*m!*StirlingS2[k, m], {m, 1, k}],{k,0,n}],{n,1,20}]}] (* Vaclav Kotesovec, May 07 2014 *)
  • PARI
    {a(n)=polcoeff(sum(m=0,n,(1/(1-x+x*O(x^n))^m-1)^m),n)}

Formula

G.f.: Sum_{n>=0} ( 1/(1-x)^n - 1 )^n.
G.f.: Sum_{n>=0} (1-x)^n / (1 + (1-x)^n)^(n+1). - Paul D. Hanna, Sep 07 2018
a(n) ~ c * d^n * n! / sqrt(n), where d = A317855 = (1+exp(1/r))*r^2 = 3.161088653865428813830172202588132491726382774188556341627278..., r = 0.8737024332396683304965683047207192982139922672025395099... is the root of the equation exp(1/r)/r + (1+exp(1/r))*LambertW(-exp(-1/r)/r) = 0, and c = 0.38377369607518184186200387319561108... . - Vaclav Kotesovec, May 07 2014

Extensions

More terms from Max Alekseyev, Feb 01 2007

A232192 G.f. satisfies: A(x) = 1 + x*Sum_{n>=0} (A(x)^n - 1)^n.

Original entry on oeis.org

1, 1, 1, 5, 44, 519, 7590, 132347, 2689046, 62644234, 1651650774, 48731341965, 1592908456996, 57173688136781, 2235773294509565, 94608603077007214, 4306708055122614542, 209823573154587335730, 10892496561736261641371, 600171728539156939466278
Offset: 0

Views

Author

Paul D. Hanna, Nov 20 2013

Keywords

Examples

			G.f.: A(x) = 1 + x + x^2 + 5*x^3 + 44*x^4 + 519*x^5 + 7590*x^6 + 132347*x^7 + 2689046*x^8 + 62644234*x^9 + 1651650774*x^10 +...
where
A(x) = 1 + x + x*(A(x)-1) + x*(A(x)^2-1)^2 + x*(A(x)^3-1)^3 + x*(A(x)^4-1)^4 + x*(A(x)^5-1)^5 + x*(A(x)^6-1)^6 + x*(A(x)^7-1)^7 +...
Also,
A(x) = 1 + x/2  +  x*A(x)/(1 + A(x))^2  +  x*A(x)^4/(1 + A(x)^2)^3  +  x*A(x)^9/(1 + A(x)^3)^4  +  x*A(x)^16/(1 + A(x)^4)^5  +  x*A(x)^25/(1 + A(x)^5)^6  + ...
		

Crossrefs

Programs

  • PARI
    {a(n)=local(A=1+x); for(i=1, n, A=1+x*sum(m=0, n, (A^m-1+x*O(x^n))^m)); polcoeff(A, n)}
    for(n=0,20,print1(a(n),", "))

Formula

G.f. satisfies:
(1) A(x) = 1 + x*Sum_{n>=0} A(x)^(n^2) / (1 + A(x)^n)^(n+1). - Paul D. Hanna, Mar 31 2018
(2) A(x) = 1 + Series_Reversion(x/G(x))
(3) A(x) = 1 + x*G(A(x)-1)
where G(x) is the g.f. of A122400, the number of square (0,1)-matrices without zero rows and with exactly n entries equal to 1.
a(n) ~ c * d^n * n! / n^(3/2), where d = A317855 = (1+exp(1/r))*r^2 = 3.161088653865428813830172202588132491726382774188556341627278..., r = 0.8737024332396683304965683047207192982139922672025395099... is the root of the equation exp(1/r)/r + (1+exp(1/r))*LambertW(-exp(-1/r)/r) = 0, and c = 0.12140554666... . - Vaclav Kotesovec, May 07 2014

A303654 G.f. A(x) satisfies: x = Sum_{n>=1} ((1+x)^n - 1)^n / A(x)^n.

Original entry on oeis.org

1, 4, 15, 110, 1319, 21626, 440406, 10567338, 289567071, 8881182506, 300677809182, 11123151634732, 446124758009229, 19278179994562787, 892894885467043254, 44130236756271133940, 2318466084626196805383, 129037338117765390406606, 7585054768393048247917776, 469612308887467564648834414
Offset: 0

Views

Author

Paul D. Hanna, May 04 2018

Keywords

Examples

			G.f.: A(x) = 1 + 4*x + 15*x^2 + 110*x^3 + 1319*x^4 + 21626*x^5 + 440406*x^6 + 10567338*x^7 + 289567071*x^8 + 8881182506*x^9 + ...
such that
x = ((1+x) - 1)/A(x) + ((1+x)^2 - 1)^2/A(x)^2 + ((1+x)^3 - 1)^3/A(x)^3 + ((1+x)^4 - 1)^4/A(x)^4 + ((1+x)^5 - 1)^5/A(x)^5 + ((1+x)^6 - 1)^6/A(x)^6 + ...
Also,
A(x) = (1+x) / ( 1/(1 + A(x)) + (1+x)/((1+x) + A(x))^2 + (1+x)^4/((1+x)^2 + A(x))^3 + (1+x)^9/((1+x)^3 + A(x))^4 + (1+x)^16/((1+x)^4 + A(x))^5 + (1+x)^25/((1+x)^5 + A(x))^6 + (1+x)^36/((1+x)^6 + A(x))^7 + ... ).
		

Programs

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

Formula

G.f.: A(x) = (1+x) / ( Sum_{n>=0} (1+x)^(n^2) / ((1+x)^n + A(x))^(n+1) ).
a(n) ~ c * d^n * n! * sqrt(n), where d = A317855 = 3.161088... and c = 0.292671... - Vaclav Kotesovec, Jun 09 2025

A326010 G.f. A(x) satisfies: 0 = Sum_{n>=1} n * ((1+x)^n - A(x))^n.

Original entry on oeis.org

1, 1, 2, 20, 282, 5134, 112053, 2823119, 80202565, 2529045393, 87523776013, 3295995672161, 134155142687732, 5869278171065418, 274718037952537674, 13701118397652347442, 725505704889894172448, 40658992718689480518864, 2404662897766073643050293, 149692182669205551972626617, 9784886698908632846522031701
Offset: 0

Views

Author

Paul D. Hanna, Jun 04 2019

Keywords

Examples

			G.f.: A(x) = 1 + x + 2*x^2 + 20*x^3 + 282*x^4 + 5134*x^5 + 112053*x^6 + 2823119*x^7 + 80202565*x^8 + 2529045393*x^9 + 87523776013*x^10 + ...
such that
0 = ((1+x) - A(x)) + 2*((1+x)^2 - A(x))^2 + 3*((1+x)^3 - A(x))^3 + 4*((1+x)^4 - A(x))^4 + 5*((1+x)^5 - A(x))^5 + 6*((1+x)^6 - A(x))^6 + ...
The terms a(n) modulo 2 begin:
1,1,0,0,0,0,1,1,1,1,1,1,0,0,0,0,0,0,1,1,1,1,1,1,
0,0,1,1,1,1,0,0,0,0,1,1,1,1,0,0,1,1,1,1,1,1,0,0,
0,0,0,0,0,0,1,1,0,0,1,1,0,0,1,1,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,0,0,1,1,1,1,
0,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,1,1,1,1,
1,1,1,1,0,0,0,0,1,1,0,0,1,1,0,0,1,1,1,1,0,0,1,1,
0,0,0,0,1,1,1,1,0,0,1,1,1,1,1,1,0,0,1,1,1,1,0,0,
1,1,0,0,0,0,1,1,1,1,0,0,0,0,1,1,1,1,0,0,0,0,0,0,
1,1,0,0,0,0,0,0,0, ...
		

Programs

  • PARI
    {a(n) = my(A=[1]); for(i=0,n, A=concat(A,0); A[#A] = polcoeff( sum(m=1,#A, m* ((1+x)^m - Ser(A))^m ), #A-1));A[n+1]}
    for(n=0,25,print1(a(n),", "))

Formula

G.f. A(x) satisfies:
(1) 0 = Sum_{n>=1} n * ((1+x)^n - A(x))^n.
(2) A(x) = P(x)/Q(x) where
P(x) = Sum_{n>=0} n * (1+x)^(n^2) / (1 + (1+x)^n*A(x))^(n+2),
Q(x) = Sum_{n>=0} (1+x)^(n*(n+1)) / (1 + (1+x)^n*A(x))^(n+2).
(3) A'(x) = P(x)/Q(x) where
P(x) = Sum_{n>=0} (n+1)^3 * ((1+x)^(n+1) - A(x))^n * (1+x)^n,
Q(x) = Sum_{n>=0} (n+1)^2 * ((1+x)^(n+1) - A(x))^n.
a(n) ~ c * d^n * sqrt(n) * n!, where d = A317855 = 3.16108865386... and c = 0.102568345138... - Vaclav Kotesovec, Jun 05 2019

A321089 G.f.: Sum_{n>=0} ((1+x)^(n+1) - 1)^n.

Original entry on oeis.org

1, 2, 10, 82, 928, 13406, 235690, 4883702, 116548222, 3148151702, 94950591878, 3162966582742, 115334767261792, 4569294561813770, 195438629679894238, 8975996556375735458, 440572146080811981406, 23015418712779922737206, 1274980039012724226987966, 74655326188457739033712062, 4607114081638141934903219532, 298862442692043953057588327202
Offset: 0

Views

Author

Paul D. Hanna, Nov 04 2018

Keywords

Examples

			G.f.: A(x) = 1 + 2*x + 10*x^2 + 82*x^3 + 928*x^4 + 13406*x^5 + 235690*x^6 + 4883702*x^7 + 116548222*x^8 + ...
		

Programs

  • PARI
    {a(n) = polcoeff( sum(k=0, n, ((1+x +x*O(x^n))^(k+1) - 1)^k), n)}
    for(n=0, 25, print1(a(n), ", "))
    
  • PARI
    /* From e.g.f. infinite series: */
    \p200 \\ set precision
    {A = Vec(round( sum(n=0, 600, 1./(1 + (1+x +O(x^26))^(-n))^(n+1)) ))}
    for(n=0, #A-1, print1(A[n+1], ", "))

Formula

Sum_{n>=0} (1+x)^(n*(n+1)) / (1 + (1+x)^n)^(n+1).
a(n) ~ c * d^n * n! / sqrt(n), where d = A317855 = 3.1610886538654288138301722... and c = 0.8785394171057422507960514834733179025314463... - Vaclav Kotesovec, Oct 04 2020
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