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.

A213593 Stirling transform of the first kind of the Lucas numbers A000032.

Original entry on oeis.org

2, 1, 2, -3, 10, -45, 250, -1645, 12490, -107415, 1031690, -10943955, 127058690, -1602400085, 21812913650, -318763741725, 4977247397650, -82695799908975, 1456703469048850, -27117356172328675, 531930264143933050
Offset: 0

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Author

Jiaqiang Pan, Jun 15 2012

Keywords

Examples

			For n=4, a(4) = r*(r-1)*(r-2)*(r-3) + s*(s-1)*(s-2)*(s-3) = 10.
		

Crossrefs

Cf. A000032 (Lucas numbers), the general-term formula of which is L(n) = r^n + s^n.

Programs

  • GAP
    Concatenation([2], List([1..25], n-> Sum([1..n], k-> (-1)^(n-k)* Stirling1(n, k)*Lucas(1,-1,k)[2] ))) # G. C. Greubel, Jul 06 2019
  • Magma
    [2] cat [(&+[StirlingFirst(n,k)*Lucas(k): k in [1..n]]): n in [1..25]]; // G. C. Greubel, Jul 06 2019
    
  • Maple
    A000032 := proc(n)
            combinat[fibonacci](n+1)+combinat[fibonacci](n-1) ;
    end proc:
    A213593 := proc(n)
            add(combinat[stirling1](n,i)*A000032(i),i=0..n) ;
    end proc:
    seq(A213593(n),n=0..20) ; # R. J. Mathar, Jun 26 2012
  • Mathematica
    Expand@FunctionExpand@Table[Gamma[2 - GoldenRatio]/Gamma[2 - GoldenRatio - n] + Gamma[1 + GoldenRatio]/Gamma[1 - n + GoldenRatio], {n, 0, 20}] (* Vladimir Reshetnikov, Oct 20 2015 *)
    Table[If[n==0, 2, Sum[StirlingS1[n, k]*LucasL[k], {k, n}]], {n, 0, 25}] (* G. C. Greubel, Jul 06 2019 *)
  • PARI
    lucas(n) = fibonacci(n+1) + fibonacci(n-1);
    vector(25, n, n--; if(n==0, 2, sum(k=1,n, stirling(n,k,1)*lucas(k)) )) \\ G. C. Greubel, Jul 06 2019
    
  • Sage
    [2]+[sum((-1)^(n-k)*stirling_number1(n,k)*lucas_number2(k,1,-1) for k in (1..n)) for n in (1..25)] # G. C. Greubel, Jul 06 2019
    

Formula

a(0)=2; for n=1,2,3, ..., a(n) = r*(r-1)*(r-2)*...*(r-n+1) + s*(s-1)*(s-2)*...*(s-n+1), where r=(1+sqrt(5))/2 and s=(1-sqrt(5))/2.
From Vladimir Reshetnikov, Oct 20 2015: (Start)
Let phi=(1+sqrt(5))/2.
a(n) = Gamma(2-phi)/Gamma(2-phi-n)+Gamma(1+phi)/Gamma(1+phi-n).
Recurrence: a(0)=2, a(1)=1, a(n+2) = (1+n-n^2)*a(n) - 2*n*a(n+1).
E.g.f.: (1+(x+1)^sqrt(5))/(x+1)^(1/phi).
(End)
a(n) ~ (-1)^n * n! * n^((sqrt(5)-3)/2) / Gamma(2/(1+sqrt(5))). - Vaclav Kotesovec, Oct 21 2015
a(n) = Sum_{k=1..n} Stirling1(n,k)*Lucas(k). - G. C. Greubel, Jul 06 2019