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.

A081179 3rd binomial transform of (0,1,0,2,0,4,0,8,0,16,...).

Original entry on oeis.org

0, 1, 6, 29, 132, 589, 2610, 11537, 50952, 224953, 993054, 4383653, 19350540, 85417669, 377052234, 1664389721, 7346972688, 32431108081, 143157839670, 631929281453, 2789470811028, 12313319895997, 54353623698786
Offset: 0

Views

Author

Paul Barry, Mar 11 2003

Keywords

Comments

Binomial transform of 0, 1, 4, 14, 48, ... (A007070 with offset 1) and second binomial transform of A000129. - R. J. Mathar, Dec 10 2011

Crossrefs

Programs

  • Magma
    I:=[0, 1]; [n le 2 select I[n] else 6*Self(n-1)-7*Self(n-2): n in [1..30]]; // Vincenzo Librandi, Aug 06 2013
  • Maple
    f:= gfun:-rectoproc({a(n) = 6*a(n-1)-7*a(n-2), a(0)=0, a(1)=1},a(n),remember):
    map(f, [$0..50]); # Robert Israel, Mar 15 2016
  • Mathematica
    CoefficientList[Series[x/(1-6 x +7 x^2), {x,0,30}], x] (* Vincenzo Librandi, Aug 06 2013 *)
    LinearRecurrence[{6,-7}, {0,1}, 41] (* G. C. Greubel, Jan 14 2024 *)
  • Sage
    [lucas_number1(n,6,7) for n in range(0, 23)] # Zerinvary Lajos, Apr 22 2009
    

Formula

a(n) = 6*a(n-1) - 7*a(n-2), a(0)=0, a(1)=1.
G.f.: x/(1-6*x+7*x^2).
a(n) = ((3+sqrt(2))^n - (3-sqrt(2))^n)/(2*sqrt(2)). [Corrected by Al Hakanson (hawkuu(AT)gmail.com), Dec 27 2008]
a(n) = 3^(n-1) Sum_{i>=0} binomial(n, 2i+1) * (2/9)^i. - Sergio Falcon, Mar 15 2016
a(n) = 2^(-1/2)*7^(n/2)*sinh(n*arcsinh(sqrt(2/7))). - Robert Israel, Mar 15 2016
E.g.f.: exp(3*x)*sinh(sqrt(2)*x)/sqrt(2). - Ilya Gutkovskiy, Aug 12 2017
a(n) = 7^((n-1)/2)*ChebyshevU(n-1, 3/sqrt(7)). - G. C. Greubel, Jan 14 2024

A164600 a(n) = 18*a(n-1) - 79*a(n-2) for n > 1; a(0) = 1, a(1) = 17.

Original entry on oeis.org

1, 17, 227, 2743, 31441, 349241, 3802499, 40854943, 434991553, 4602307457, 48477201539, 509007338599, 5332433173201, 55772217368297, 582637691946467, 6081473282940943, 63438141429166081, 661450156372654961
Offset: 0

Views

Author

Klaus Brockhaus, Aug 17 2009

Keywords

Comments

Binomial transform of A081185 without initial term 0. Ninth binomial transform of A164587.
This sequence is part of a class of sequences defined by the recurrence a(n,m) = 2*(m+1)*a(n-1,m) - ((m+1)^2 - 2)*a(n-2,m) with a(0) = 1 and a(1) = m+9. The generating function is Sum_{n>=0} a(n,m)*x^n = (1 - (m-7)*x)/(1 - 2*(m+1)*x + ((m+1)^2 - 2)*x^2) and has a series expansion in terms of Pell-Lucas numbers defined by a(n, m) = (1/2)*Sum_{k=0..n} binomial(n,k)*m^(n-k)*(5*Q(k) + 4*Q(k-1)). - G. C. Greubel, Mar 12 2021

Crossrefs

Sequences in the class a(n, m): A164298 (m=1), A164299 (m=2), A164300 (m=3), A164301 (m=4), A164598 (m=5), A164599 (m=6), A081185 (m=7), this sequence (m=8).

Programs

  • Magma
    [ n le 2 select 16*n-15 else 18*Self(n-1)-79*Self(n-2): n in [1..18] ];
    
  • Maple
    m:=30; S:=series( (1-x)/(1-18*x+79*x^2), x, m+1):
    seq(coeff(S, x, j), j=0..m); # G. C. Greubel, Mar 12 2021
  • Mathematica
    LinearRecurrence[{18,-79},{1,17},30] (* Harvey P. Dale, Oct 30 2013 *)
  • PARI
    my(x='x+O('x^50)); Vec((1-x)/(1-18*x+79*x^2)) \\ G. C. Greubel, Aug 11 2017
    
  • Sage
    [( (1-x)/(1-18*x+79*x^2) ).series(x,n+1).list()[n] for n in (0..30)] # G. C. Greubel, Mar 12 2021

Formula

a(n) = ((1+4*sqrt(2))*(9+sqrt(2))^n + (1-4*sqrt(2))*(9-sqrt(2))^n)/2.
G.f.: (1-x)/(1-18*x+79*x^2).
E.g.f.: exp(9*x)*(cosh(sqrt(2)*x) + 4*sqrt(2)*sinh(sqrt(2)*x)). - G. C. Greubel, Aug 11 2017
From G. C. Greubel, Mar 12 2021: (Start)
a(n) = 2*A147960(n) + 8*A153593(n).
a(n) = (1/2)*Sum_{k=0..n} binomial(n,k)*8^(n-k)*(5*Q(k) + 4*Q(k-1)), where Q(n) = Pell-Lucas(n) = A002203(n). (End)

A171700 Triangle T : T(n,k)= A007318(n,k)*a(n-k) with a(0)=0 and a(n)= A077957(n-1) for n>0.

Original entry on oeis.org

0, 1, 0, 0, 2, 0, 2, 0, 3, 0, 0, 8, 0, 4, 0, 4, 0, 20, 0, 5, 0, 0, 24, 0, 40, 0, 6, 0, 8, 0, 84, 0, 70, 0, 7, 0, 0, 64, 0, 224, 0, 112, 0, 8, 0, 16, 0, 288, 0, 504, 0, 168, 0, 9, 0, 0, 160, 0, 960, 0, 1008, 0, 240, 0, 10, 0
Offset: 0

Views

Author

Philippe Deléham, Dec 15 2009

Keywords

Comments

Diagonal sums : A001353(n+1) alternating with zeros.

Examples

			Triangle begins : 0 ; 1,0 ; 0,2,0 ; 2,0,3,0 ; 0,8,0,4,0 ; 4,0,20,0,5,0 ; ...
		

Formula

Sum_{k, 0<=k<=n} T(n,k)*x^k = A077957(n-1), A000129(n), A007070(n-1), A081179(n), A081180(n), A081182(n), A081183(n), A081184(n), A081185(n), A153593(n) for x = 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 respectively.
Showing 1-3 of 3 results.