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 1-2 of 2 results.

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

A085391 Square array of centered numbers, read by antidiagonals.

Original entry on oeis.org

0, 1, 0, 1, 1, 0, 1, 3, 1, 0, 1, 4, 5, 1, 0, 1, 5, 10, 7, 1, 0, 1, 6, 15, 19, 9, 1, 0, 1, 7, 21, 35, 31, 11, 1, 0, 1, 8, 28, 56, 69, 46, 13, 1, 0, 1, 9, 36, 84, 126, 121, 64, 15, 1, 0, 1, 10, 45, 120, 210, 251, 195, 85, 17, 1, 0, 1, 11, 55, 165, 330, 462, 456, 295, 109, 19, 1, 0
Offset: 0

Views

Author

Paul Barry, Jul 02 2003

Keywords

Examples

			Rows begin
0 0 0 0 0 0 ...
1 1 1 1 1 1 ...
1 3 5 7 9 11 ...
1 4 10 19 31 46 ...
1 5 15 35 69 121...
		

Crossrefs

Formula

Square array T(n, k)=C(n+k, k)-C(n, k).
Row k has g.f. (1-x^k)/(1-x)^(k+1).
Showing 1-2 of 2 results.