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

A292751 a(n) = n!*A063019(n).

Original entry on oeis.org

0, 1, 2, 6, 24, 240, 5040, 110880, 2298240, 47900160, 1117670400, 31654022400, 1064820556800, 39404587622400, 1532420002713600, 62512065487872000, 2723498636931072000, 128376129298120704000, 6524556605528113152000, 352829667414210674688000
Offset: 0

Views

Author

N. J. A. Sloane, Sep 22 2017

Keywords

Crossrefs

Cf. A063019.

Programs

  • Mathematica
    nmax = 20; CoefficientList[InverseSeries[x - x^2 + x^3 - x^4 + O[x]^(nmax+1), x], x]*Range[0, nmax]! (* Jean-François Alcover, Jan 21 2019 *)
  • PARI
    seq(n)=Vec(serlaplace(serreverse(x - x^2 + x^3 - x^4 + O(x*x^n))), -(n+1)) \\ Andrew Howroyd, Nov 11 2018

Extensions

Offset changed to zero and more terms added by Robert Price, Oct 19 2017

A063022 Reversion of y - y^2 - y^3 - y^5.

Original entry on oeis.org

0, 1, 1, 3, 10, 39, 161, 698, 3126, 14360, 67276, 320229, 1544257, 7528577, 37044530, 183733552, 917598103, 4610484729, 23289784660, 118209987295, 602556082765, 3083273829240, 15832177371585, 81554320766310, 421320423560400, 2182395044437686, 11332298321692704
Offset: 0

Views

Author

Olivier Gérard, Jul 05 2001

Keywords

Crossrefs

Programs

  • Maple
    with(gfun):
    F:= RootOf(y-y^2-y^3-y^5-x,y):
    DE:=holexprtodiffeq(F,g(x)):
    Rec:= diffeqtorec(DE,g(x),a(n)):
    f:= rectoproc(Rec,a(n),remember):
    map(f, [$0..50]); # Robert Israel, Jan 08 2019
  • Mathematica
    CoefficientList[InverseSeries[Series[y - y^2 - y^3 - y^5, {y, 0, 30}], x], x]
  • Sage
    def Reversion(gf, n=30):
        R = PowerSeriesRing(QQ, 'x', n)
        x = R.gen().O(n)
        return list(R(gf).reverse())
    Reversion(x - x^2 - x^3 - x^5, 24) # Peter Luschny, Jan 08 2019

Formula

D-finite with recurrence 575*n*(n-1)*(n-2)*(n-3)*(20979233391541*n -77947280254859)*a(n) -(n-1)*(n-2)*(n-3)*(61583500097488301*n^2 -316279381660643613*n +324795527443572336)*a(n-1) -(n-2)*(n-3)*(38717301341634153*n^3 -324199735605145484*n^2 +891613204581594443*n -818427098922228360)*a(n-2) +5*(n-3)*(15150509582201525*n^4 -167218351234002005*n^3 +671920281600084880*n^2 -1156419009962856700*n +711178431524070144)*a(n-3) +5*(-11728771987556875*n^5 +177923469670928750*n^4 -1042517573106816125*n^3 +2912399220423080050*n^2 -3791544816675160464*n +1751906653132562208)*a(n-4) -125*(5*n-26)*(5*n-22)*(5*n-23)*(73773273715*n-209652025983)*(5*n-24)*a(n-5)=0. - R. J. Mathar, Mar 21 2022

A366024 Expansion of (1/x) * Series_Reversion( x*(1-x)*(1+x^5) ).

Original entry on oeis.org

1, 1, 2, 5, 14, 41, 125, 393, 1265, 4147, 13799, 46488, 158261, 543610, 1881730, 6557818, 22990323, 81026013, 286915275, 1020294605, 3642192301, 13047053600, 46885795710, 168979132425, 610640337099, 2212116899436, 8031940264223, 29224761233788
Offset: 0

Views

Author

Seiichi Manyama, Sep 26 2023

Keywords

Crossrefs

Programs

  • Mathematica
    CoefficientList[InverseSeries[Series[x(1-x)(1+x^5),{x,0,28}],x]/x,x]  (* Stefano Spezia, Sep 26 2023 *)
  • PARI
    a(n) = sum(k=0, n\5, (-1)^k*binomial(n+k, n)*binomial(2*n-5*k, n))/(n+1);

Formula

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

A063023 Reversion of y - y^2 - y^4 - y^5.

Original entry on oeis.org

0, 1, 1, 2, 6, 21, 77, 292, 1143, 4592, 18821, 78364, 330512, 1409149, 6063526, 26298592, 114849110, 504595293, 2228824203, 9891723114, 44087704836, 197255893945, 885630834120, 3988872011820, 18017892014655
Offset: 0

Views

Author

Olivier Gérard, Jul 05 2001

Keywords

Crossrefs

Programs

  • Maple
    with(gfun):
    F:= RootOf(y-y^2-y^4-y^5-x, y):
    DE:=holexprtodiffeq(F, g(x)):
    Rec:= diffeqtorec(DE, g(x), a(n)):
    f:= rectoproc(Rec, a(n), remember):
    map(f, [$0..50]);# Robert Israel, Jan 08 2019
  • Mathematica
    CoefficientList[InverseSeries[Series[y - y^2 - y^4 - y^5, {y, 0, 30}], x], x]
  • Maxima
    a(n):=sum((sum(binomial(j,n-k-2*j-1)*binomial(k,j),j,floor((n-k-1)/3),floor((n-k-1)/2)))*binomial(n+k-1,n-1),k,0,n-1)/n; /* Vladimir Kruchinin, May 26 2011 */
    
  • PARI
    concat(0, Vec(serreverse(x - x^2 - x^4 - x^5 + O(x^30)))) \\ Michel Marcus, Jan 08 2019
  • Sage
    # uses[Reversion from A063022]
    Reversion(x - x^2 - x^4 - x^5, 25) # Peter Luschny, Jan 08 2019
    

Formula

a(n) = sum(k=0..n-1, (sum(j=floor((n-k-1)/3)..floor((n-k-1)/2), binomial(j,n-k-2*j-1)*binomial(k,j)))*binomial(n+k-1,n-1))/n, n>0, a(0)=0. - Vladimir Kruchinin, May 26 2011
D-finite with recurrence 500*n*(n-1)*(n-2)*(n-3)*(2749734646741*n -12465511712206)*a(n) -4350*(n-1)*(n-2)*(n-3)*(1671932639004*n^2 -9463993359665*n +8542758180998)*a(n-1) +6*(n-2)*(n-3)*(920566361953318*n^3 -5234275380165135*n^2 +1599947907526062*n + 14550951937253720)*a(n-2) -58*(n-3)*(141125952976394*n^4 -1372074713192783*n^3 +3865929553111591*n^2 -1368848933612182*n -5017756051156800)*a(n-3) +3*(-5087969954630151*n^5 +92718860230184360*n^4 -673277365411431865*n^3 +2437688480550464340*n^2 -4405429911017929324*n +3182000337895328880)*a(n-4) -145*(5*n-22)*(5*n-23)*(5*n-26)*(48367137647*n -140254765035)*(5*n-24)*a(n-5)=0. - R. J. Mathar, Mar 21 2022

A063026 Reversion of y - y^2 + y^4 - y^5.

Original entry on oeis.org

0, 1, 1, 2, 4, 9, 21, 52, 135, 368, 1045, 3068, 9230, 28245, 87414, 272544, 854012, 2685897, 8473107, 26805994, 85045674, 270599945, 863529480, 2763745020, 8870777955, 28550721966, 92128996782, 298004209496, 966085311052
Offset: 0

Views

Author

Olivier Gérard, Jul 05 2001

Keywords

Crossrefs

Cf. A063019.

Programs

  • Mathematica
    CoefficientList[InverseSeries[Series[y - y^2 + y^4 - y^5, {y, 0, 30}], x], x]

Formula

a(n+1) = (1/(n+1)) * Sum_{k=0..floor(n/3)} (-1)^k * binomial(n+k,n) * binomial(2*n-3*k,n). - Seiichi Manyama, Sep 26 2023

A364552 G.f. satisfies A(x) = 1 + x*A(x) + x^4*A(x)^3.

Original entry on oeis.org

1, 1, 1, 1, 2, 5, 11, 21, 39, 78, 169, 373, 808, 1727, 3719, 8153, 18100, 40315, 89770, 200250, 448755, 1010685, 2284295, 5173961, 11740697, 26699780, 60863291, 139045991, 318247190, 729572315, 1675085099, 3851795549, 8869990949, 20453679944, 47223844863
Offset: 0

Views

Author

Seiichi Manyama, Jul 28 2023

Keywords

Crossrefs

Programs

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

Formula

a(n) = Sum_{k=0..floor(n/4)} binomial(n-k,3*k) * binomial(3*k,k) / (2*k+1).

A366023 Expansion of (1/x) * Series_Reversion( x*(1-x)*(1+x^4) ).

Original entry on oeis.org

1, 1, 2, 5, 13, 36, 104, 309, 940, 2915, 9184, 29328, 94747, 309180, 1017824, 3376693, 11279274, 37906330, 128085630, 434913555, 1483226921, 5078436800, 17450556480, 60159492600, 208013078910, 721205983737, 2506764055592, 8733076109732, 30489081691750
Offset: 0

Views

Author

Seiichi Manyama, Sep 26 2023

Keywords

Crossrefs

Programs

  • Mathematica
    CoefficientList[InverseSeries[Series[x(1-x)(1+x^4),{x,0,29}],x]/x,x]  (* Stefano Spezia, Sep 26 2023 *)
  • PARI
    a(n) = sum(k=0, n\4, (-1)^k*binomial(n+k, n)*binomial(2*n-4*k, n))/(n+1);

Formula

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

A217365 Series reversion of x + x^2 + x^3 + x^4 + x^5.

Original entry on oeis.org

1, -1, 1, -1, 1, 0, -6, 27, -83, 209, -455, 845, -1169, 272, 5916, -29070, 98040, -274075, 660859, -1351756, 2110020, -1186110, -8227260, 47128770, -170898624, 505121130, -1281947030, 2772309230, -4708067030, 3936320480, 13030540120, -90168747031, 348836671587, -1077316101393
Offset: 1

Views

Author

R. J. Mathar, Oct 01 2012

Keywords

Comments

Appears to obey an 8-term hypergeometric recurrence with 4th-order polynomial coefficients.

Examples

			If y=x+x^2+x^3+x^4+x^5, then x=y -y^2 +y^3 -y^4 +y^5 -6*y^7 +27*y^8 -83*y^9 +...
		

Crossrefs

Cf. A063019 (x-x^2+x^3-x^4), A103779 (x+x^2+x^3).

Programs

  • Maple
    rec := 5*n*(5*n-1)*(5*n+1)*(5*n+2)*(5*n+3)*a(n)-(n+1)*(27906*n^4+198109*n^3+447051*n^2+405674*n+128400)*a(n+1)+(25*(n+2))*(1875*n^4+28312*n^3+141513*n^2+287228*n+204072)*a(n+2)+(250*(n+2))*(n+3)*(250*n^3+3031*n^2+11433*n+13668)*a(n+3)+(625*(n+2))*(n+3)*(n+4)*(75*n^2+662*n+1403)*a(n+4)+(3125*(n+2))*(n+3)*(n+4)*(n+5)*(6*n+29)*a(n+5)+(3125*(n+2))*(n+3)*(n+4)*(n+5)*(n+6)*a(n+6):
    f:= gfun:-rectoproc({rec,a(1) = 1, a(2) = -1, a(3) = 1, a(4) = -1, a(5) = 1, a(6) = 0},a(n),remember):
    map(f, [$1..50]); # Robert Israel, Jul 10 2015
  • Mathematica
    InverseSeries[x + x^2 + x^3 + x^4 + x^5 + O[x]^50][[3]] (* Vladimir Reshetnikov, Jul 09 2015 *)
    RecurrenceTable[{5 (-8+3 n) (-21+5 n) (-19+5 n) (-18+5 n) (-17+5 n) (-17+6 n) (-11+6 n) a[-4+n]+4 (-3+n) (-11+6 n) (-4792620+7647427 n-4855116 n^2+1533029 n^3-240768 n^4+15048 n^5) a[-3+n]+30 (-3+n) (-2+n) (-1267420+2386123 n-1760222 n^2+636639 n^3-113004 n^4+7884 n^5) a[-2+n]+100 (-3+n) (-2+n) (-1+n) (-23+6 n) (-2310+2921 n-1152 n^2+144 n^3) a[-1+n]+125 (-3+n) (-2+n) (-1+n) n (-11+3 n) (-23+6 n) (-17+6 n) a[n]==0, a[1]==1, a[2]==-1, a[3]==1, a[4]==-1}, a, {n, 1, 40}] (* Vaclav Kotesovec, Aug 18 2015 *)
  • PARI
    Vec(serreverse(x + x^2 + x^3 + x^4 + x^5 + O(x^50))) \\ Michel Marcus, Aug 03 2015

Formula

D-finite with recurrence: 5 n (5 n - 1) (5 n + 1) (5 n + 2) (5 n + 3) a(n) - (n + 1) (27906 n^4 + 198109 n^3 + 447051 n^2 + 405674 n + 128400) a(n + 1) + 25 (n + 2) (1875 n^4 + 28312 n^3 + 141513 n^2 + 287228 n + 204072) a(n + 2) + 250 (n + 2) (n + 3) (250 n^3 + 3031 n^2 + 11433 n + 13668) a(n + 3) + 625 (n + 2) (n + 3) (n + 4) (75 n^2 + 662 n + 1403) a(n + 4) + 3125 (n + 2) (n + 3) (n + 4) (n + 5) (6 n + 29) a(n + 5) + 3125(n + 2) (n + 3) (n + 4) (n + 5) (n + 6) a(n + 6) = 0. - Vladimir Reshetnikov, Jul 09 2015
From Robert Israel, Jul 10 2015: (Start)
G.f. G(x) satisfies G + G^2 + G^3 + G^4 + G^5 = x
and the differential equation
-2184*x^3+32760*x^2-163800*x+273000+(-10920*x^3+163800*x^2-819000*x+1365000)*G(x)+(2457000*x^4-24555336*x^3+33314040*x^2-22930200*x-10608000)*G'(x)+(11602500*x^5-88671024*x^4+64015500*x^3-18674400*x^2-27414000*x-9780000)*G''(x)+(7962500*x^6-48147528*x^5+12768480*x^4-2457200*x^3-7171500*x^2-6885000*x-1975000)*G'''(x)+(1137500*x^7-5485909*x^6-750720*x^5-1121525*x^4-654500*x^3-744375*x^2-475000*x-109375)*G''''(x) = 0
from which we can obtain the 8-term recurrence mentioned in the Comments:
1820*(5*n+1)*(5*n+2)*(5*n+3)*(5*n-1)*a(n)-13*(421993*n^4+2859670*n^3+6398855*n^2+5850050*n+1876272)*a(n+1)-60*(12512*n^4-187784*n^3-1717861*n^2-4206649*n-3230668)*a(n+2)-25*(44861*n^4+367454*n^3+1830175*n^2+6002422*n+7768608)*a(n+3)-500*(n+4)*(1309*n^3+22197*n^2+140942*n+279612)*a(n+4)-1875*(n+5)*(n+4)*(397*n^2+5657*n+18614)*a(n+5)-25000*(19*n+136)*(n+6)*(n+5)*(n+4)*a(n+6)-109375*(n+5)*(n+4)*(n+7)*(n+6)*a(n+7) = 0.
From the Lagrange inversion theorem,
a(n) = 1/n! * (d/dx)^(n-1) (p^n)(0) where p(x) = 1/(1+x+x^2+x^3+x^4).
(End)
Recurrence: 125*(n-3)*(n-2)*(n-1)*n*(3*n - 11)*(6*n - 23)*(6*n - 17)*a(n) = -100*(n-3)*(n-2)*(n-1)*(6*n - 23)*(144*n^3 - 1152*n^2 + 2921*n - 2310)*a(n-1) - 30*(n-3)*(n-2)*(7884*n^5 - 113004*n^4 + 636639*n^3 - 1760222*n^2 + 2386123*n - 1267420)*a(n-2) - 4*(n-3)*(6*n - 11)*(15048*n^5 - 240768*n^4 + 1533029*n^3 - 4855116*n^2 + 7647427*n - 4792620)*a(n-3) - 5*(3*n - 8)*(5*n - 21)*(5*n - 19)*(5*n - 18)*(5*n - 17)*(6*n - 17)*(6*n - 11)*a(n-4). - Vaclav Kotesovec, Aug 18 2015

A364539 G.f. satisfies A(x) = 1 + x*A(x) + x^3*A(x)^5.

Original entry on oeis.org

1, 1, 1, 2, 7, 22, 62, 182, 583, 1928, 6358, 21063, 70888, 241889, 831634, 2874584, 9995579, 34966279, 122938956, 434062141, 1538378816, 5471697241, 19525345791, 69880082323, 250767909528, 902123110483, 3252793321513, 11753570922933, 42553831219830
Offset: 0

Views

Author

Seiichi Manyama, Jul 28 2023

Keywords

Crossrefs

Programs

  • PARI
    a(n) = sum(k=0, n\3, binomial(n+2*k, 5*k)*binomial(5*k, k)/(4*k+1));

Formula

a(n) = Sum_{k=0..floor(n/3)} binomial(n+2*k,5*k) * binomial(5*k,k) / (4*k+1).

A365756 G.f. satisfies A(x) = 1 + x*A(x) / (1 - x^3*A(x)^4).

Original entry on oeis.org

1, 1, 1, 1, 2, 7, 22, 58, 142, 363, 1014, 2966, 8645, 24824, 71189, 206742, 609159, 1809493, 5388804, 16073002, 48092377, 144532884, 436168716, 1320372837, 4006489208, 12183544414, 37132838866, 113426618425, 347191793705, 1064688271730, 3270387354434
Offset: 0

Views

Author

Seiichi Manyama, Sep 18 2023

Keywords

Crossrefs

Programs

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

Formula

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