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 1-4 of 4 results.

A135741 E.g.f.: A(x) = Sum_{n>=0} exp(Fibonacci(n)*x) * x^n/n!.

Original entry on oeis.org

1, 1, 3, 7, 19, 71, 347, 2115, 16395, 164071, 2099991, 34138963, 706636219, 18658538939, 627640554659, 26870678088831, 1464622985216331, 101659649883242575, 8983370274289495947, 1010460953826963080371
Offset: 0

Views

Author

Paul D. Hanna, Nov 27 2007

Keywords

Examples

			E.g.f.: A(x) = 1 + x + 3*x^2/2! + 7*x^3/3! + 19*x^4/4! + 71*x^5/5! + 347*x^6/6! +...
where
A(x) = 1 + exp(x)*x + exp(x)*x^2/2! + exp(2*x)*x^3/3! + exp(3*x)*x^4/4! + exp(5*x)*x^5/5! + exp(8*x)*x^6/6! + exp(13*x)*x^7/7! + exp(21*x)*x^8/8! +...
		

Crossrefs

Programs

  • Mathematica
    Flatten[{1,Table[Sum[Binomial[n,k]*Fibonacci[k]^(n-k),{k,0,n}],{n,1,20}]}] (* Vaclav Kotesovec, Jul 14 2014 *)
  • PARI
    {a(n)=sum(k=0,n,binomial(n,k)*fibonacci(k)^(n-k))}
    
  • PARI
    {a(n)=n!*polcoeff(sum(k=0,n,exp(fibonacci(k)*x +x*O(x^n))*x^k/k!),n)}
    
  • PARI
    {a(n)=polcoeff(sum(k=0, n, x^k/(1-fibonacci(k)*x +x*O(x^n))^(k+1)), n)}

Formula

a(n) = Sum_{k=0..n} C(n,k) * Fibonacci(k)^(n-k).
O.g.f.: Sum_{n>=0} x^n/(1 - Fibonacci(n)*x)^(n+1).
a(n) ~ c * 2^(n+1/2) * ((1+sqrt(5))/2)^(n^2/4) / (sqrt(Pi*n) * 5^(n/4)), where c = Sum_{k=-infinity..infinity} 5^(k/2)*((1+sqrt(5))/2)^(-k^2) = 3.5769727481316948565395...(see A219781) if n is even, and c = Sum_{k=-infinity..infinity} 5^((k+1/2)/2)*((1+sqrt(5))/2)^(-(k+1/2)^2) = 3.5769727390073366345992... if n is odd. - Vaclav Kotesovec, Jul 14 2014

A210342 Row sums of triangle A210341.

Original entry on oeis.org

1, 2, 4, 9, 24, 78, 317, 1636, 10752, 89871, 955536, 12930172, 222618065, 4874855542, 135781292308, 4811103270053, 216847500834512, 12432143862756778, 906625645142897789, 84102571511631809864, 9923979699312024569440, 1489546408205976627946331
Offset: 0

Views

Author

Emanuele Munarini, Mar 20 2012

Keywords

Crossrefs

Cf. A210341.

Programs

  • Magma
    [&+[Fibonacci(n-k+2)^k: k in [0..n]]: n in [0..21]]; // Bruno Berselli, Mar 28 2012
  • Mathematica
    Table[Sum[Fibonacci[n - k + 2]^k, {k, 0, n}], {n, 0, 100}]
  • Maxima
    makelist(sum(fib(n-k+2)^k,k,0,n),n,0,12);
    

Formula

G.f.: Sum_{k>=0} x^k/(1-Fibonacci(k+2)*x).
a(n) = [x^n] Sum_{k=0..n} x^k/(1-Fibonacci(k+2)*x).
a(n) = A135961(n+2)-1. - Vaclav Kotesovec, Jan 05 2013

A187780 Sum_{k=0..n} Lucas(k)^(n-k).

Original entry on oeis.org

1, 3, 6, 13, 31, 84, 271, 1111, 6096, 44965, 434321, 5388944, 85434621, 1727597731, 44466614106, 1455616862597, 60619117448531, 3211943842710212, 216483614502128251, 18558646821817827015, 2023790814160269113876, 280732940929438329958733, 49535201863823517417076181
Offset: 0

Views

Author

Vaclav Kotesovec, Jan 05 2013

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Sum[LucasL[k]^(n-k), {k, 0, n}], {n, 0, 20}]
    (* constants: *)
    ceven = N[Sum[((1+Sqrt[5])/2)^(-k^2), {k, -Infinity, +Infinity}], 50]
    codd = N[Sum[((1+Sqrt[5])/2)^(-(k+1/2)^2), {k, -Infinity, +Infinity}], 50]
  • PARI
    Lucas(n)=fibonacci(n-1)+fibonacci(n+1)
    a(n)=sum(k=0, n, Lucas(k)^(n-k))
    for(n=0,21,print1(a(n),", ")) \\ Paul D. Hanna, Jan 05 2013

Formula

a(n) ~ c * ((1+sqrt(5))/2)^(n^2/4), where c = Sum_{k=-Infinity..Infinity} ((1+sqrt(5))/2)^(-k^2) = 2.555093469444518777230568... if n is even and c = Sum_{k=-Infinity..Infinity} ((1+sqrt(5))/2)^(-(k+1/2)^2) = 2.555093456793304790966994... if n is odd
G.f.: A(x) = Sum_{n>=0} x^n/(1 - Lucas(n)*x).

A219781 Decimal expansion of Sum_{n = -infinity..infinity} 5^(n/2)*((1+sqrt(5))/2)^(-n^2).

Original entry on oeis.org

3, 5, 7, 6, 9, 7, 2, 7, 4, 8, 1, 3, 1, 6, 9, 4, 8, 5, 6, 5, 3, 9, 5, 1, 9, 7, 8, 4, 8, 5, 6, 3, 7, 4, 5, 3, 7, 5, 2, 8, 4, 0, 5, 3, 6, 5, 2, 3, 5, 2, 2, 2, 3, 0, 7, 7, 3, 6, 9, 7, 2, 7, 3, 7, 6, 1, 2, 6, 1, 7, 5, 8, 2, 7, 8, 1, 1, 1, 2, 7, 1, 7, 5, 7, 3, 0, 2
Offset: 1

Views

Author

Vaclav Kotesovec, Nov 29 2012

Keywords

Comments

Constant is associated with A135961.

Examples

			3.5769727481316948565395...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[N[Sum[5^(k/2)*((1+Sqrt[5])/2)^(-k^2), {k,-Infinity,Infinity}], 131], 10, 130][[1]]
Showing 1-4 of 4 results.