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.

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A153026 a(1)=0, a(n) = n^3 - a(n-1).

Original entry on oeis.org

0, 8, 19, 45, 80, 136, 207, 305, 424, 576, 755, 973, 1224, 1520, 1855, 2241, 2672, 3160, 3699, 4301, 4960, 5688, 6479, 7345, 8280, 9296, 10387, 11565, 12824, 14176, 15615, 17153, 18784, 20520, 22355, 24301, 26352, 28520, 30799, 33201, 35720, 38368
Offset: 1

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Author

Keywords

Comments

The old name was: a(n)+a(n+1) = cube: 0+8=8=2^3; 8+19=27=3^3; 19+45=64=4^3; ...

Crossrefs

Programs

  • Magma
    [n le 1 select n-1 else n^3-Self(n-1): n in [1..50]]; // Vincenzo Librandi, May 19 2014
  • Mathematica
    a=1;lst={};Do[a=n^3-a;AppendTo[lst,a],{n,1,5!}];lst
    CoefficientList[Series[x (8 - 5 x + 4 x^2 - x^3)/((1 + x) (1 - x)^4), {x, 0, 50}], x] (* Vincenzo Librandi, May 19 2014 *)

Formula

From R. J. Mathar, Dec 19 2008: (Start)
G.f.: x^2*(8-5*x+4*x^2-x^3)/((1+x)*(1-x)^4).
a(n)+a(n+1) = A000578(n+1).
a(n)= -1/8+3*n^2/4+n^3/2+9*(-1)^n/8. (End)

Extensions

Name improved by Alex Ratushnyak, Aug 05 2012

A215097 a(n) = n^3 - a(n-2) for n >= 2 and a(0)=0, a(1)=1.

Original entry on oeis.org

0, 1, 8, 26, 56, 99, 160, 244, 352, 485, 648, 846, 1080, 1351, 1664, 2024, 2432, 2889, 3400, 3970, 4600, 5291, 6048, 6876, 7776, 8749, 9800, 10934, 12152, 13455, 14848, 16336, 17920, 19601, 21384, 23274, 25272, 27379, 29600, 31940, 34400, 36981, 39688, 42526
Offset: 0

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Author

Alex Ratushnyak, Aug 03 2012

Keywords

Crossrefs

Cf. A000217 (n^2 - a(n-1)).
Cf. A125577 (n^2 - a(n-1) with a(0)=1).
Cf. A011934 (n^3 - a(n-1)).
Cf. A153026 (n^3 - a(n-1) with a(1)=0).
Cf. A194274 (n^2 - a(n-2)).
Cf. A187093 (n^2 - a(n-2) with a(0)=a(1)=1, a(-1)=0).
Cf. A107386 ((n-2)^2 - a(n-1) with a(0)=0, a(1)=a(2)=1, a(3)=2).
Cf. A206481 ((n-1)^3 - a(n-2)).

Programs

  • Mathematica
    RecurrenceTable[{a[0] == 0, a[1] == 1, a[n] == n^3 - a[n - 2]}, a[n], {n, 0, 43}] (* Bruno Berselli, Aug 07 2012 *)
  • Python
    prpr = 0
    prev = 1
    for n in range(2,77):
        print(prpr, end=',')
        curr = n*n*n - prpr
        prpr = prev
        prev = curr

Formula

G.f.: (x+4*x^2+x^3)/((-1+x)^4*(1+x^2)). - David Scambler, Aug 06 2012
a(n) = (n*(n^2-3)-(1-(-1)^n)*i^(n+1))/2, where i=sqrt(-1). - Bruno Berselli, Aug 07 2012
Showing 1-2 of 2 results.