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 11-19 of 19 results.

A104473 a(n) = binomial(n+2,2)*binomial(n+6,2).

Original entry on oeis.org

15, 63, 168, 360, 675, 1155, 1848, 2808, 4095, 5775, 7920, 10608, 13923, 17955, 22800, 28560, 35343, 43263, 52440, 63000, 75075, 88803, 104328, 121800, 141375, 163215, 187488, 214368, 244035, 276675, 312480, 351648, 394383, 440895, 491400, 546120, 605283, 669123
Offset: 0

Views

Author

Zerinvary Lajos, Apr 18 2005

Keywords

Examples

			a(0) = C(0+2,2)*C(0+6,2) = C(2,2)*C(6,2) = 1*15 = 155.
a(6) = 1*3*5 + 2*4*6 + 3*5*7 + 4*6*8 + 5*7*9 + 6*8*10 + 7*9*11 = 1848.
		

Crossrefs

Subsequence of A085780.

Programs

  • Magma
    [Binomial(n+2, 2)*Binomial(n+6, 2): n in [0..50]]; // Vincenzo Librandi, Apr 28 2014
    
  • Mathematica
    f[n_] := Binomial[n + 2, 2] Binomial[n + 6, 2]; Table[f[n], {n,0,40}] (* Robert G. Wilson v, Apr 20 2005 *)
    CoefficientList[Series[3 (5-4*x+x^2)/(1-x)^5, {x,0,40}], x] (* Vincenzo Librandi, Apr 28 2014 *)
  • PARI
    a(n)=binomial(n+2,2)*binomial(n+6,2) \\ Charles R Greathouse IV, Jun 07 2013
    
  • SageMath
    def A104473(n): return binomial(n+2,2)*binomial(n+6,2)
    print([A104473(n) for n in range(51)]) # G. C. Greubel, Mar 05 2025

Formula

a(n) = (1/4)*(n+1)*(n+2)*(n+5)*(n+6).
a(n) = A034856(n+2)^2 - 1. - J. M. Bergot, Dec 14 2010
G.f.: 3*(5-4*x+x^2)/(1-x)^5. - Colin Barker, Sep 21 2012
a(n) = Sum_{i=1..n+1} i*(i+2)*(i+4). - Bruno Berselli, Apr 28 2014
a(n) = A000217(n)*A000217(n+4) = 3*A033275(n+4). - R. J. Mathar, Nov 29 2015
From Amiram Eldar, Aug 30 2022: (Start)
Sum_{n>=0} 1/a(n) = 43/450.
Sum_{n>=0} (-1)^n/a(n) = 16*log(2)/15 - 154/225. (End)
From G. C. Greubel, Mar 05 2025: (Start)
a(n) = 90*A000579(n+6)/A000279(n+3).
E.g.f.: (1/4)*(60 + 192*x + 114*x^2 + 20*x^3 + x^4)*exp(x). (End)

A104475 a(n) = binomial(n+4,4) * binomial(n+8,4).

Original entry on oeis.org

70, 630, 3150, 11550, 34650, 90090, 210210, 450450, 900900, 1701700, 3063060, 5290740, 8817900, 14244300, 22383900, 34321980, 51482970, 75710250, 109359250, 155405250, 217567350, 300450150, 409704750, 552210750, 736281000, 971890920, 1270934280, 1647507400, 2118223800
Offset: 0

Views

Author

Zerinvary Lajos, Apr 18 2005

Keywords

Examples

			a(0): C(0+4,4)*C(0+8,4) = C(4,4)*C(8,4) = 1*70 = 70.
a(7): C(5+4,4)*C(5+8,4) = C(9,4)*(13,4) = 126*715 = 90090.
		

Crossrefs

Programs

  • Magma
    [Binomial(n+4,4)*Binomial(n+8,4): n in [0..30]]; // Vincenzo Librandi, Jul 31 2015
    
  • Maple
    A104475:=n->binomial(n+4,4)*binomial(n+8,4): seq(A104475(n), n=0..40); # Wesley Ivan Hurt, Jan 29 2017
  • Mathematica
    f[n_] := Binomial[n + 4, 4]Binomial[n + 8, 4]; Table[ f[n], {n, 0, 25}] (* Robert G. Wilson v, Apr 20 2005 *)
  • PARI
    vector(30, n, n--; binomial(n+4,4)*binomial(n+8,4)) \\ Michel Marcus, Jul 31 2015
    
  • SageMath
    def A104475(n): return binomial(n+4,4)*binomial(n+8,4)
    print([A104475(n) for n in range(31)]) # G. C. Greubel, Mar 05 2025

Formula

a(n) = 70*A000581(n-8). - Michel Marcus, Jul 31 2015
From Amiram Eldar, Aug 30 2022: (Start)
Sum_{n>=0} 1/a(n) = 4/245.
Sum_{n>=0} (-1)^n/a(n) = 512*log(2)/35 - 37216/3675. (End)
From G. C. Greubel, Mar 05 2025: (Start)
G.f.: 70/(1-x)^9.
E.g.f.: (1/576)*(40320 + 322560*x + 564480*x^2 + 376320*x^3 + 117600*x^4 + 18816*x^5 + 1568*x^6 + 64*x^7 + x^8)*exp(x). (End)

Extensions

More terms from Robert G. Wilson v, Apr 20 2005

A104476 a(n) = binomial(n+7,7)*binomial(n+11,7).

Original entry on oeis.org

330, 6336, 61776, 411840, 2123550, 9060480, 33372768, 109219968, 324246780, 886828800, 2261413440, 5427392256, 12352970916, 26829982080, 55895796000, 112183843200, 217706770710, 409800980160, 750266946000, 1339149240000, 2335141487250, 3985308138240
Offset: 0

Views

Author

Zerinvary Lajos, Apr 18 2005

Keywords

Examples

			a(0): C(0+7,7)*C(0+11,7) = C(7,7)*C(11,7) = 1*330 = 330;
a(7): C(7+7,7)*C(7+11,7) = C(14,7)*C(18,7) = 3432*31824 = 109219968.
		

Crossrefs

Cf. A062264.

Programs

  • Magma
    [Binomial(n+7,7)*Binomial(n+11,7): n in [0..30]]; // Vincenzo Librandi, Jul 31 2015
    
  • Mathematica
    f[n_] := Binomial[n + 7, 7]*Binomial[n + 11, 7]; Table[ f[n], {n, 0, 19}] (* Robert G. Wilson v, Apr 20 2005 *)
  • PARI
    vector(30, n, n--; binomial(n+7,7)*binomial(n+11,7)) \\ Michel Marcus, Jul 31 2015
    
  • Python
    A104476_list, m = [], [3432, -1716, 660, 330, 330, 330, 330, 330, 330, 330, 330, 330, 330, 330, 330]
    for _ in range(10**2):
        A104476_list.append(m[-1])
        for i in range(14):
            m[i+1] += m[i] # Chai Wah Wu, Dec 15 2015
    
  • SageMath
    def A104476(n): return binomial(n+7,7)*binomial(n+11,7)
    print([A104476(n) for n in range(31)]) # G. C. Greubel, Mar 04 2025

Formula

From Amiram Eldar, Sep 01 2022: (Start)
Sum_{n>=0} 1/a(n) = 539*Pi^2 - 114905813/21600.
Sum_{n>=0} (-1)^n/a(n) = 1741019/7200 - 49*Pi^2/2. (End)
G.f.: 66*(5 + 21*x + 21*x^2 + 5*x^3)/(1-x)^15. - G. C. Greubel, Mar 04 2025

Extensions

More terms from Robert G. Wilson v, Apr 20 2005

A104478 a(n) = binomial(n+8,8)*binomial(n+12,8).

Original entry on oeis.org

495, 11583, 135135, 1061775, 6370650, 31286970, 131405274, 486370170, 1621233900, 4946841900, 13992495660, 37058912748, 92647281870, 220089696750, 499568676750, 1088533853550, 2285921092455, 4642276728375, 9143878404375, 17513561154375, 32691980821500, 59592810754620
Offset: 0

Views

Author

Zerinvary Lajos, Apr 18 2005

Keywords

Comments

All terms are multiples of 99. - Michel Marcus, Aug 01 2015

Examples

			a(0): C(0+8,8)*C(0+12,8) = C(8,8)*C(12,8) = 1*495 = 495.
a(7): C(7+8,8)*C(7+12,8) = C(15,8)*C(19,8) = 6435*75582 = 486370170.
		

Crossrefs

Programs

  • Magma
    [Binomial(n+8,8)*Binomial(n+12,8): n in [0..30]]; // Vincenzo Librandi, Jul 31 2015
    
  • Mathematica
    f[n_] := Binomial[n + 8, 8] * Binomial[n + 12, 8]; Table[ f[n], {n, 0, 18}] (* Robert G. Wilson v, Apr 19 2005 *)
  • PARI
    vector(30, n, n--; binomial(n+8,8)*binomial(n+12,8)) \\ Michel Marcus, Jul 31 2015
    
  • SageMath
    def A104478(n): return binomial(n+8,8)*binomial(n+12,8)
    print([A104478(n) for n in range(31)]) # G. C. Greubel, Mar 04 2025

Formula

a(n) = A000581(n+8)*A000581(n+12). - Michel Marcus, Aug 01 2015
From Amiram Eldar, Sep 04 2022: (Start)
Sum_{n>=0} 1/a(n) = 11648*Pi^2/3 - 65726161036/1715175.
Sum_{n>=0} (-1)^n/a(n) = 262144*log(2)/99 - 629604992/343035. (End)
G.f.: 99*(5 + 32*x + 56*x^2 + 32*x^3 + 5*x^4)/(1-x)^17. - G. C. Greubel, Mar 04 2025

Extensions

Corrected and extended by Robert G. Wilson v, Apr 19 2005
a(6) corrected by Georg Fischer, May 08 2021

A105249 a(n) = binomial(n+2,n)*binomial(n+6,n).

Original entry on oeis.org

1, 21, 168, 840, 3150, 9702, 25872, 61776, 135135, 275275, 528528, 965328, 1689324, 2848860, 4651200, 7379904, 11415789, 17261937, 25573240, 37191000, 53183130, 74890530, 103980240, 142506000, 192976875, 258434631, 342540576, 449672608, 585033240, 754769400
Offset: 0

Views

Author

Zerinvary Lajos, Apr 14 2005

Keywords

Examples

			a(0): C(0+2,0)*C(0+6,0) = C(2,0)*C(6,0) = 1*1 = 1;
a(10): C(10+2,10)*C(10+6,10) = C(12,10)*C(16,10) = 66*8008 = 528528.
		

Crossrefs

Cf. A062264.

Programs

  • Magma
    [Binomial(n+2,n)*Binomial(n+6,n): n in [0..30]]; // Vincenzo Librandi, Jul 31 2015
    
  • Mathematica
    f[n_] := Binomial[n + 2, n]Binomial[n + 6, n]; Table[ f[n], {n, 0, 27}] (* Robert G. Wilson v, Apr 20 2005 *)
    LinearRecurrence[{9,-36,84,-126,126,-84,36,-9,1},{1,21,168,840,3150,9702,25872,61776,135135},30] (* Harvey P. Dale, Oct 08 2012 *)
  • SageMath
    def A105249(n): return binomial(n+2,n)*binomial(n+6,n)
    print([a105249(n) for n in range(31)]) # G. C. Greubel, Mar 04 2025

Formula

a(0)=1, a(1)=21, a(2)=168, a(3)=840, a(4)=3150, a(5)=9702, a(6)=25872, a(7)=61776, a(8)=135135, a(n) = 9*a(n-1) -36*a(n-2) +84*a(n-3) -126*a(n-4) +126*a(n-5) -84*a(n-6) +36*a(n-7) -9*a(n-8) +a(n-9). - Harvey P. Dale, Oct 08 2012
G.f.: (1+12*x+15*x^2)/(1-x)^9. - Colin Barker, Jan 21 2013
From Amiram Eldar, Sep 04 2022: (Start)
Sum_{n>=0} 1/a(n) = 12*Pi^2 - 5869/50.
Sum_{n>=0} (-1)^n/a(n) = 256*log(2)/5 - 4*Pi^2 + 371/75. (End)
E.g.f.: (1/1440)*(1440 + 28800*x + 91440*x^2 + 95520*x^3 + 42900*x^4 + 9312*x^5 + 1010*x^6 + 52*x^7 + x^8)*exp(x). - G. C. Greubel, Mar 04 2025

Extensions

More terms from Robert G. Wilson v, Apr 20 2005

A105250 a(n) = binomial(n+3,n)*binomial(n+7,n).

Original entry on oeis.org

1, 32, 360, 2400, 11550, 44352, 144144, 411840, 1061775, 2516800, 5562128, 11583936, 22926540, 43411200, 79070400, 139163904, 237557133, 394558560, 639331000, 1013012000, 1572701130, 2396496960, 3589794000, 5293080000, 7691506875, 11026544256, 15610063392
Offset: 0

Views

Author

Zerinvary Lajos, Apr 14 2005

Keywords

Examples

			a(0): C(0+3,0)*C(0+7,0) = C(3,0)*C(7,0) = 1*1 = 1;
a(10): C(10+3,10)*C(10+7,10) = C(13,10)*(17,10) = 286*19448 = 5562128.
		

Crossrefs

Cf. A062264.

Programs

  • Magma
    [Binomial(n+3,n)*Binomial(n+7,n): n in [0..30]]; // Vincenzo Librandi, Jul 31 2015
    
  • Mathematica
    f[n_] := Binomial[n + 3, n]Binomial[n + 7, n]; Table[ f[n], {n, 0, 23}] (* Robert G. Wilson v, Apr 20 2005 *)
  • SageMath
    def A105250(n): return binomial(n+3,n)*binomial(n+7,n)
    print([A105250(n) for n in range(31)]) # G. C. Greubel, Mar 04 2025

Formula

G.f.: (1+21*x+63*x^2+35*x^3)/(1-x)^11. - Colin Barker, Jan 21 2013
a(n) = 11*a(n-1) -55*a(n-2) +165*a(n-3) -330*a(n-4) +462*a(n-5) -462*a(n-6) +330*a(n-7) -165*a(n-8) +55*a(n-9) -11*a(n-10) +a(n-11). - Wesley Ivan Hurt, May 24 2021
From Amiram Eldar, Sep 01 2022: (Start)
Sum_{n>=0} 1/a(n) = 98*Pi^2 - 72464/75.
Sum_{n>=0} (-1)^n/a(n) = 7*Pi^2 + 1792*log(2)/5 - 15827/50. (End)

Extensions

More terms from Robert G. Wilson v, Apr 20 2005

A105252 a(n) = binomial(n+5,n)*binomial(n+9,n).

Original entry on oeis.org

1, 60, 1155, 12320, 90090, 504504, 2312310, 9060480, 31286970, 97337240, 277411134, 733649280, 1818838840, 4261894560, 9502285320, 20271542016, 41572498275, 82281899700, 157706974425, 293570877600, 532097215650, 941124327000, 1627522854750, 2756636064000
Offset: 0

Views

Author

Zerinvary Lajos, Apr 14 2005

Keywords

Examples

			a(0): C(0+5,0)*C(0+9,0) = C(5,0)*C(9,0) = 1*1 = 1;
a(10): C(10+5,10)*C(10+9,10) = C(15,10)*(19,10) = 3003*92378 = 277411134.
		

Crossrefs

Cf. A062264.

Programs

  • Magma
    [Binomial(n+5,n)*Binomial(n+9,n): n in [0..30]]; // Vincenzo Librandi, Jul 31 2015
    
  • Mathematica
    f[n_] := Binomial[n + 5, n]Binomial[n + 9, n]; Table[ f[n], {n, 0, 20}] (* Robert G. Wilson v, Apr 20 2005 *)
  • Python
    A105252_list, m = [], [2002, -4433, 3487, -1133, 127, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1]
    for _ in range(10**2):
        A105252_list.append(m[-1])
        for i in range(14):
            m[i+1] += m[i] # Chai Wah Wu, Dec 15 2015
    
  • SageMath
    def A105252(n): return binomial(n+5,n)*binomial(n+9,n)
    print([A105252(n) for n in range(31)]) # G. C. Greubel, Mar 04 2025

Formula

G.f.: (1+45*x+360*x^2+840*x^3+630*x^4+126*x^5)/(1-x)^15. - Colin Barker, Jan 21 2013
From Amiram Eldar, Sep 01 2022: (Start)
Sum_{n>=0} 1/a(n) = 7425*Pi^2/2 - 114902691/3136.
Sum_{n>=0} (-1)^n/a(n) = 28960047/15680 - 255*Pi^2/4 - 12288*log(2)/7. (End)

Extensions

More terms from Robert G. Wilson v, Apr 20 2005

A105253 a(n) = binomial(n+6,n)*binomial(n+10,n).

Original entry on oeis.org

1, 77, 1848, 24024, 210210, 1387386, 7399392, 33372768, 131405274, 462351890, 1479526048, 4365213216, 12004336344, 31040798712, 76018282560, 177375992640, 396324483555, 851617661895, 1766318113560, 3547314771000, 6917263803450, 13128684361650, 24304341297600
Offset: 0

Views

Author

Zerinvary Lajos, Apr 14 2005

Keywords

Examples

			a(0): C(0+6,0)*C(0+10,0) = C(6,0)*C(10,0) = 1*1 = 1;
a(10): C(10+6,10)*C(10+10,10) = C(16,10)*(20,10) = 8008*184756 = 1479526048.
		

Crossrefs

Cf. A062264.

Programs

  • Magma
    [Binomial(n+6,n)*Binomial(n+10,n): n in [0..30]]; // Vincenzo Librandi, Jul 31 2015
    
  • Mathematica
    f[n_] := Binomial[n + 6, n]Binomial[n + 10, n]; Table[ f[n], {n, 0, 20}] (* Robert G. Wilson v, Apr 20 2005 *)
  • Python
    A105253_list, m = [], [8008, -22022, 23023, -11297, 2563, -209] + [1]*11
    for _ in range(10**2):
        A105253_list.append(m[-1])
        for i in range(16):
            m[i+1] += m[i] # Chai Wah Wu, Jan 24 2016
    
  • SageMath
    def A105253(n): return binomial(n+6,n)*binomial(n+10,n)
    print([A105253(n) for n in range(31)]) # G. C. Greubel, Mar 04 2025

Formula

G.f.: (1 + 60*x + 675*x^2 + 2400*x^3 + 3150*x^4 + 1513*x^5 + 210*x^6)/(1-x)^17. - Colin Barker, Jan 21 2013
From Amiram Eldar, Sep 01 2022: (Start)
Sum_{n>=0} 1/a(n) = 20020*Pi^2 - 1493768807/7560.
Sum_{n>=0} (-1)^n/a(n) = 131072*log(2)/21 - 100*Pi^2 - 88332653/26460. (End)

Extensions

More terms from Robert G. Wilson v, Apr 20 2005

A105254 a(n) = binomial(n+7,n)*binomial(n+11,n).

Original entry on oeis.org

1, 96, 2808, 43680, 450450, 3459456, 21237216, 109219968, 486370170, 1921462400, 6859620768, 22449667968, 68128506264, 193501082880, 518306472000, 1317650231040, 3196331224515, 7432299594720, 16630917303000, 35933837940000, 75191555889450, 152770145299200
Offset: 0

Views

Author

Zerinvary Lajos, Apr 14 2005

Keywords

Examples

			a(0): C(0+7,0)*C(0+11,0) = C(7,0)*C(11,0) = 1*1 = 1;
a(8): C(8+7,8)*C(8+11,8) = C(15,8)*(19,8) = 6435*75582 = 486370170.
		

Crossrefs

Cf. A062264.

Programs

  • Magma
    [Binomial(n+7,n)*Binomial(n+11,n): n in [0..30]]; // Vincenzo Librandi, Jul 31 2015
    
  • Mathematica
    f[n_] := Binomial[n + 7, n]Binomial[n + 11, n]; Table[ f[n], {n, 0, 19}] (* Robert G. Wilson v, Apr 20 2005 *)
  • SageMath
    def A105254(n): return binomial(n+7,n)*binomial(n+11,n)
    print([A105254(n) for n in range(31)]) # G. C. Greubel, Mar 04 2025

Formula

G.f.: (1 + 77*x + 1155*x^2 + 5775*x^3 + 11550*x^4 + 9702*x^5 + 3234*x^6 + 330*x^7)/(1-x)^19. - Colin Barker, Jan 21 2013
From Amiram Eldar, Sep 04 2022: (Start)
Sum_{n>=0} 1/a(n) = 308308*Pi^2/3 - 16431524791/16200.
Sum_{n>=0} (-1)^n/a(n) = 1232*Pi^2/3 + 360448*log(2)/45 - 108911693/11340. (End)

Extensions

More terms from Robert G. Wilson v, Apr 20 2005
More terms from Colin Barker, Jan 21 2013
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