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 10 results.

A094100 Fit a polynomial of degree k-1 to column k of array in A048790, evaluate it at dimension n = -1.

Original entry on oeis.org

1, -2, 9, -64, 560, -5370, 53788, -555864, 5957685, -66459200, 763983132, -8919566196, 105678848821, -1286858544734
Offset: 1

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Author

Keywords

Comments

Might be thought of as number of rooted (-1)-dimensional "polycubes" with n cells, with no symmetries removed.

References

  • Dan Hoey, Bill Gosper and Richard C. Schroeppel, Discussions in Math-Fun Mailing list, circa Jul 13 1999.

Crossrefs

Extensions

a(9)-a(14) using Luther & Mertens's formulas added by Andrei Zabolotskii, Jun 27 2025

A094161 Column 5 of A048790.

Original entry on oeis.org

0, 5, 315, 2670, 10810, 30475, 69405, 137340, 246020, 409185, 642575, 963930, 1392990, 1951495, 2663185, 3553800, 4651080, 5984765, 7586595, 9490310, 11731650, 14348355, 17380165, 20868820, 24858060, 29393625, 34523255, 40296690, 46765670, 53983935, 62007225
Offset: 1

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Author

N. J. A. Sloane, May 05 2004

Keywords

References

  • Dan Hoey, Bill Gosper and Richard C. Schroeppel, Discussions in Math-Fun Mailing list, circa Jul 13 1999.

Programs

  • PARI
    concat(0, Vec(-5*x^2*(112*x^3+229*x^2+58*x+1)/(x-1)^5 + O(x^100))) \\ Colin Barker, Feb 28 2015

Formula

a(n) = 5*(n-1) + 305*C(n-1,2) + 1740*C(n-1,3) + 2000*C(n-1,4) where C(n,k) is the binomial coefficient. - Joshua Zucker, Aug 14 2006
a(n) = 5*(672-1715*n+1595*n^2-652*n^3+100*n^4)/6. - Colin Barker, Feb 28 2015
G.f.: -5*x^2*(112*x^3+229*x^2+58*x+1) / (x-1)^5. - Colin Barker, Feb 28 2015

Extensions

More terms from Joshua Zucker, Aug 14 2006

A094160 Column 4 of A048790.

Original entry on oeis.org

0, 4, 76, 344, 936, 1980, 3604, 5936, 9104, 13236, 18460, 24904, 32696, 41964, 52836, 65440, 79904, 96356, 114924, 135736, 158920, 184604, 212916, 243984, 277936, 314900, 355004, 398376, 445144, 495436, 549380, 607104, 668736, 734404, 804236
Offset: 1

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Author

N. J. A. Sloane, May 05 2004

Keywords

References

  • Dan Hoey, Bill Gosper and Richard C. Schroeppel, Discussions in Math-Fun Mailing list, circa Jul 13 1999.

Programs

  • Magma
    [64/3*n^3-30*n^2+38/3*n: n in [0..60]]; // Vincenzo Librandi, Aug 28 2016
    
  • Mathematica
    Table[(64/3 n^3 - 30 n^2 + 38/3 n), {n, 0, 80}] (* Vincenzo Librandi, Aug 28 2016 *)
  • PARI
    concat(0, Vec(4*x^2*(1+15*x+16*x^2)/(1-x)^4 + O(x^60))) \\ Colin Barker, Aug 28 2016

Formula

A polynomial in n of degree 3.
a(n) = 64/3 n^3 - 30 n^2 + 38/3 n. - Joshua Zucker, Aug 14 2006
From Colin Barker, Aug 28 2016: (Start)
a(n) = 4*a(n-1)-6*a(n-2)+4*a(n-3)-a(n-4) for n>4.
G.f.: 4*x^2*(1+15*x+16*x^2) / (1-x)^4.
(End)

Extensions

More terms from Joshua Zucker, Aug 14 2006

A094159 3 times hexagonal numbers: a(n) = 3*n*(2*n-1).

Original entry on oeis.org

0, 3, 18, 45, 84, 135, 198, 273, 360, 459, 570, 693, 828, 975, 1134, 1305, 1488, 1683, 1890, 2109, 2340, 2583, 2838, 3105, 3384, 3675, 3978, 4293, 4620, 4959, 5310, 5673, 6048, 6435, 6834, 7245, 7668, 8103, 8550, 9009, 9480, 9963, 10458, 10965, 11484
Offset: 0

Views

Author

N. J. A. Sloane, May 05 2004

Keywords

Comments

Column 3 of A048790.
Sequence found by reading the line from 0, in the direction 0, 3, ..., in the square spiral whose vertices are the generalized pentagonal numbers A001318. - Omar E. Pol, Sep 08 2011
a(n) is the sum of all perimeters of triangles having two sides of length n. For n=4 one has seven triangles with two sides of length 4 and the other of lengths 1..7. - J. M. Bergot, Mar 26 2014
a(n) is the Wiener index of the complete tripartite graph K_{n,n,n}. - Eric W. Weisstein, Sep 07 2017
Sequence found by reading the line from 0, in the direction 0, 3, ..., in a spiral on an equilateral triangular lattice. - Hans G. Oberlack, Dec 08 2018

References

  • Dan Hoey, Bill Gosper and Richard C. Schroeppel, Discussions in Math-Fun Mailing list, circa Jul 13 1999.

Crossrefs

Essentially a bisection of A045943. - Omar E. Pol, Sep 17 2011
Cf. numbers of the form n*(n*k-k+6)/2, this sequence is the case k=12: see Comments lines of A226492.

Programs

Formula

a(n) = 6*n^2 - 3*n = 3*n*(2*n-1) = 3*A000384(n). - Omar E. Pol, Dec 11 2008
a(n) = 12*n + a(n-1) - 9 with n > 0, a(0)=0. - Vincenzo Librandi, Nov 16 2010
G.f.: 3*x*(1+3*x)/(1-x)^3. - Bruno Berselli, Jan 21 2011
Sum_{n>0} 1/a(n) = (2/3)*log(2). - Enrique Pérez Herrero, Jun 04 2015
E.g.f.: 3*x*(1+2*x)*exp(x). - G. C. Greubel, Dec 07 2018
Sum_{n>=1} (-1)^(n+1)/a(n) = Pi/6 - log(2)/3. - Amiram Eldar, Jan 10 2022

Extensions

More terms from Vladimir Joseph Stephan Orlovsky, Nov 16 2008
Definition improved, offset corrected and edited by Omar E. Pol, Dec 11 2008

A048663 Number of rooted polycubes with n cells, with no symmetries removed.

Original entry on oeis.org

1, 6, 45, 344, 2670, 20886, 164514, 1303304, 10375830, 82947380, 665440039, 5354470860, 43196001173, 349254823554, 2829388506690, 22961191276080, 186622811691276, 1518914831183982, 12377727000122043
Offset: 1

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Author

Richard C. Schroeppel, Dan Hoey

Keywords

Comments

"Rooted" means some cell of the polycube is designated as the origin. This has the effect of multiplying the count by the volume of the polycube.

Examples

			There are six dicubes, each consisting of the origin cube together with one adjacent cube, in each of the six directions.
		

References

  • Dan Hoey, Bill Gosper and Richard C. Schroeppel, Discussions in Math-Fun Mailing list, circa Jul 13 1999.

Crossrefs

A row of the array in A048790.
Cf. A001931.

Programs

Formula

a(n) = n * A001931(n). - Andrew Howroyd, Dec 04 2018

Extensions

a(12)-a(19) from Andrew Howroyd, Dec 04 2018

A048668 Number of rooted 7-dimensional "polycubes" with n cells, with no symmetries removed.

Original entry on oeis.org

1, 14, 273, 5936, 137340, 3307878, 81972296, 2075032808, 53403322203, 1392729138920, 36718293579198, 976872759337356, 26189947759482689, 706808197553825794
Offset: 1

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Author

Keywords

Crossrefs

Row 7 of A048790.

Formula

a(n) = n * A151833(n). - Andrew Howroyd, Dec 05 2018

Extensions

a(8)-a(14) from Andrew Howroyd, Dec 05 2018

A094101 Number of rooted 8-dimensional "polycubes" with n cells, with no symmetries removed.

Original entry on oeis.org

1, 16, 360, 9104, 246020, 6940128, 201819688, 6003642144, 181770021702, 5581576203840, 173384554507648, 5438172832075920
Offset: 1

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Author

Keywords

References

  • Dan Hoey, Bill Gosper and Richard C. Schroeppel, Discussions in Math-Fun Mailing list, circa Jul 13 1999.

Crossrefs

Formula

a(n) = n * A151834(n). - Andrew Howroyd, Dec 05 2018

Extensions

a(9)-a(12) from Andrew Howroyd, Dec 05 2018

A048666 Number of rooted 5-dimensional "polycubes" with n cells, with no symmetries removed.

Original entry on oeis.org

1, 10, 135, 1980, 30475, 483702, 7847525, 129419240, 2161766520, 36481155310, 620845213890, 10640356142700, 183453873965570, 3179310190998270, 55345614317169210
Offset: 1

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Author

Keywords

Crossrefs

Row 5 of A048790.

Formula

a(n) = n * A151831(n). - Andrew Howroyd, Dec 05 2018

Extensions

a(9)-a(15) from Andrew Howroyd, Dec 05 2018

A048667 Number of rooted 6-dimensional "polycubes" with n cells, with no symmetries removed.

Original entry on oeis.org

1, 12, 198, 3604, 69405, 1386048, 28403620, 593399416, 12584663901, 270123960220, 5855607723702, 127986261470436, 2817048848634449, 62378907950601228, 1388516401122627270
Offset: 1

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Author

Keywords

Crossrefs

Row 6 of A048790.

Formula

a(n) = n * A151832(n). - Andrew Howroyd, Dec 05 2018

Extensions

a(9)-a(15) from Andrew Howroyd, Dec 05 2018
a(13) corrected by Andrei Zabolotskii, Jun 27 2025

A048665 Number of rooted 4-dimensional "polycubes" with n cells, with no symmetries removed.

Original entry on oeis.org

1, 8, 84, 936, 10810, 127632, 1531180, 18589840, 227826873, 2813450960, 34963217388, 436807761192, 5482017092760, 69070750692496, 873243394317660, 11073530439895728
Offset: 1

Views

Author

Keywords

Crossrefs

Row 4 of A048790.

Formula

a(n) = n * A151830(n). - Andrew Howroyd, Dec 05 2018

Extensions

a(10)-a(16) from Andrew Howroyd, Dec 05 2018
Showing 1-10 of 10 results.