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 11-12 of 12 results.

A046757 Triangle of coefficients of certain polynomials (exponents in decreasing order).

Original entry on oeis.org

1, 2, 1, 5, 5, 1, 30, 30, 10, 1, 272, 272, 102, 17, 1, 3250, 3250, 1300, 260, 26, 1, 47952, 47952, 19980, 4440, 555, 37, 1, 840350, 840350, 360150, 85750, 12250, 1050, 50, 1, 17039360, 17039360, 7454720, 1863680, 291200, 29120, 1820, 65, 1, 392203458
Offset: 0

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Author

Keywords

Examples

			Triangle begins:
  {1};
  {2,1};
  {5,5,1};
  {30,30,10,1};
  {272,272,102,17,1};
  ....
E.g. third row {5,5,1} corresponds to polynomial q(3,x)= 5*x^2+5*x+1.
		

Crossrefs

x*p(k-1, -x)/q(k, -x), with the row polynomials p(n, x) from triangle A033842(n, m) is for k=1..5 g.f. for A000079 (powers of two), A039717, A043553, A045624, A046088, respectively.

Formula

a(n, n) = 1, a(n, m) = (1+n^2)*binomial(n, m)*n^(n-m-2), n>m >= 0, else 0.

A093132 Third binomial transform of Fibonacci(3n+2).

Original entry on oeis.org

1, 8, 60, 440, 3200, 23200, 168000, 1216000, 8800000, 63680000, 460800000, 3334400000, 24128000000, 174592000000, 1263360000000, 9141760000000, 66150400000000, 478668800000000, 3463680000000000, 25063424000000000
Offset: 0

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Author

Paul Barry, Mar 23 2004

Keywords

Crossrefs

Programs

  • GAP
    a:=[1,8];; for n in [2..30] do a[n]:=10*(a[n-1]-2*a[n-2]); od; a; # G. C. Greubel, Dec 27 2019
  • Magma
    I:=[1,8]; [n le 2 select I[n] else 10*(Self(n-1) - 2*Self(n-2)): n in [1..30]]; // G. C. Greubel, Dec 27 2019
    
  • Maple
    seq(coeff(series((1-2*x)/(1-10*x+20*x^2), x, n+1), x, n), n = 0..30); # G. C. Greubel, Dec 27 2019
  • Mathematica
    Table[If[EvenQ[n], 2^n*5^(n/2)*Fibonacci[n+2], 2^n*5^((n-1)/2)*LucasL[n+2]], {n, 0, 30}] (* G. C. Greubel, Dec 27 2019 *)
  • PARI
    my(x='x+O('x^30)); Vec((1-2*x)/(1-10*x+20*x^2)) \\ G. C. Greubel, Dec 27 2019
    
  • Sage
    def A093132_list(prec):
        P. = PowerSeriesRing(ZZ, prec)
        return P( (1-2*x)/(1-10*x+20*x^2) ).list()
    A093132_list(30) # G. C. Greubel, Dec 27 2019
    

Formula

G.f.: (1-2*x)/(1-10*x+20*x^2).
a(n) = ( (5 + 3*sqrt(5))*(5 + sqrt(5))^n + (5 - 3*sqrt(5))*(5 - sqrt(5))^n)/10.
a(n) = 2^n*A039717(n).
a(2*n) = 4^n*5^n*Fibonacci(2*n+2), a(2*n+1) = 2^(2*n+1)*5^n*Lucas(2*n+3). - G. C. Greubel, Dec 27 2019
Previous Showing 11-12 of 12 results.