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 1-3 of 3 results.

A222408 Partial sums of A008531, or crystal ball sequence for {A_4}* lattice.

Original entry on oeis.org

1, 11, 61, 211, 551, 1201, 2311, 4061, 6661, 10351, 15401, 22111, 30811, 41861, 55651, 72601, 93161, 117811, 147061, 181451, 221551, 267961, 321311, 382261, 451501, 529751, 617761, 716311, 826211, 948301, 1083451
Offset: 0

Views

Author

N. J. A. Sloane, Feb 21 2013

Keywords

Crossrefs

Programs

Formula

a(n) = (4+10*n+15*n^2+10*n^3+5*n^4)/4. G.f.: -(x^4+6*x^3+16*x^2+6*x+1) / (x-1)^5. [Colin Barker, Mar 08 2013]

A226449 a(n) = n*(5*n^2-8*n+5)/2.

Original entry on oeis.org

0, 1, 9, 39, 106, 225, 411, 679, 1044, 1521, 2125, 2871, 3774, 4849, 6111, 7575, 9256, 11169, 13329, 15751, 18450, 21441, 24739, 28359, 32316, 36625, 41301, 46359, 51814, 57681, 63975, 70711, 77904, 85569, 93721, 102375, 111546, 121249, 131499, 142311, 153700
Offset: 0

Views

Author

Bruno Berselli, Jun 07 2013

Keywords

Comments

Sequences of the type b(m)+m*b(m-1), where b is a polygonal number:
A006003(n) = A000217(n) + n*A000217(n-1) (b = triangular numbers);
A069778(n) = A000290(n+1) + (n+1)*A000290(n) (b = square numbers);
A143690(n) = A000326(n+1) + (n+1)*A000326(n) (b = pentagonal numbers);
A212133(n) = A000384(n) + n*A000384(n-1) (b = hexagonal numbers);
a(n) = A000566(n) + n*A000566(n-1) (b = heptagonal numbers);
A226450(n) = A000567(n) + n*A000567(n-1) (b = octagonal numbers);
A226451(n) = A001106(n) + n*A001106(n-1) (b = nonagonal numbers);
A204674(n) = A001107(n+1) + (n+1)*A001107(n) (b = decagonal numbers).

Crossrefs

Programs

  • Magma
    [n*(5*n^2-8*n+5)/2: n in [0..40]];
    
  • Magma
    I:=[0,1,9,39]; [n le 4 select I[n] else 4*Self(n-1)-6*Self(n-2)+4*Self(n-3)-Self(n-4): n in [1..45]]; // Vincenzo Librandi, Aug 18 2013
    
  • Mathematica
    Table[n (5 n^2 - 8 n + 5)/2, {n, 0, 40}]
    CoefficientList[Series[x (1 + 5 x + 9 x^2)/(1 - x)^4, {x, 0, 45}], x] (* Vincenzo Librandi, Aug 18 2013 *)
    LinearRecurrence[{4,-6,4,-1},{0,1,9,39},50] (* Harvey P. Dale, May 19 2017 *)
  • PARI
    a(n)=n*(5*n^2-8*n+5)/2 \\ Charles R Greathouse IV, Oct 07 2015

Formula

G.f.: x*(1+5*x+9*x^2)/(1-x)^4.
a(n) - a(-n) = A008531(n) for n>0.

A008487 Expansion of (1-x^5) / (1-x)^5.

Original entry on oeis.org

1, 5, 15, 35, 70, 125, 205, 315, 460, 645, 875, 1155, 1490, 1885, 2345, 2875, 3480, 4165, 4935, 5795, 6750, 7805, 8965, 10235, 11620, 13125, 14755, 16515, 18410, 20445, 22625, 24955, 27440, 30085, 32895, 35875, 39030, 42365, 45885, 49595, 53500, 57605, 61915
Offset: 0

Views

Author

Keywords

Comments

Related to the 4-dimensional cyclotomic lattice Z[zeta_5] (or A_4^{*}).
Growth series of the affine Weyl group of type A4. - Paul E. Gunnells, Jan 06 2017

References

  • R. Bott, The geometry and the representation theory of compact Lie groups, in: Representation Theory of Lie Groups, in: London Math. Soc. Lecture Note Ser., vol. 34, Cambridge University Press, Cambridge, 1979, pp. 65-90.
  • J. V. Uspensky and M. A. Heaslet, Elementary Number Theory, McGraw-Hill, NY, 1939, p. 158.

Crossrefs

Programs

  • GAP
    concatenation([1], List([1..50], n-> 5*n*(n^2 +5)/6)); # G. C. Greubel, Nov 07 2019
  • Magma
    [1] cat [5*n*(n^2 +5)/6: n in [1..50]]; // G. C. Greubel, Nov 07 2019
    
  • Maple
    1, seq(5*n*(n^2 +5)/6, n=1..50); # G. C. Greubel, Nov 07 2019
  • Mathematica
    CoefficientList[Series[(1-x^5)/(1-x)^5, {x, 0, 50}], x] (* Stefano Spezia, Dec 30 2018 *)
  • PARI
    Vec((1-x^5) / (1-x)^5+O(x^50)) \\ Charles R Greathouse IV, Sep 26 2012; corrected by Colin Barker, Jan 06 2017
    
  • Sage
    [1]+[5*n*(n^2 +5)/6 for n in (1..50)] # G. C. Greubel, Nov 07 2019
    

Formula

a(n) is the sum of 5 consecutive tetrahedral (or pyramidal) numbers: C(n+3,3) = (n+1)(n+2)(n+3)/6 = A000292(n) for n>0, a(0) = 1. a(n) = A000292(n-4) + A000292(n-3) + A000292(n-2) + A000292(n-1) + A000292(n) for n>0, a(0) = 1. - Alexander Adamchuk, May 20 2006
Equals binomial transform of [1, 4, 6, 4, 1, -1, 1, -1, 1, ...]. - Gary W. Adamson, Apr 29 2008
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4) for n > 4. - Colin Barker, Jan 06 2017
For n >= 1, a(n) = (5*n^3 + 25*n)/6. - Christopher Hohl, Dec 30 2018
E.g.f.: 1 + x*(30 + 15*x + 5*x^2)*exp(x)/6. - G. C. Greubel, Nov 07 2019
Showing 1-3 of 3 results.