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.

A207834 G.f.: exp( Sum_{n>=1} 5*L(n)*x^n/n ), where L(n) = Fibonacci(n-1)^n + Fibonacci(n+1)^n.

Original entry on oeis.org

1, 5, 25, 130, 1295, 38861, 4227075, 1309117220, 1123176929475, 2564594183278115, 15604715134340991949, 251021373648740285348860, 10668788238489683954523431475, 1195322752666989652479885363067075, 352750492054485236937115646128341734205
Offset: 0

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Author

Paul D. Hanna, Feb 20 2012

Keywords

Comments

Given g.f. A(x), note that A(x)^(1/5) is not an integer series.
Compare the definition to the g.f. of the Fibonacci numbers:
1/(1-x-x^2) = exp( Sum_{n>=1} Lucas(n)*x^n/n ), where Lucas(n) = Fibonacci(n-1) + Fibonacci(n+1).

Examples

			G.f.: A(x) = 1 + 5*x + 25*x^2 + 130*x^3 + 1295*x^4 + 38861*x^5 +...
such that, by definition,
log(A(x))/5 = x + 5*x^2/2 + 28*x^3/3 + 641*x^4/4 + 33011*x^5/5 +...+ (Fibonacci(n-1)^n + Fibonacci(n+1)^n)*x^n/n +...
		

Crossrefs

Programs

  • PARI
    {L(n)=fibonacci(n-1)^n+fibonacci(n+1)^n}
    {a(n)=polcoeff(exp(sum(m=1,n,5*L(m)*x^m/m)+x*O(x^n)),n)}
    for(n=0,51,print1(a(n),", "))

A165937 G.f.: A(x) = exp( Sum_{n>=1} A002203(n^2)*x^n/n ).

Original entry on oeis.org

1, 2, 19, 964, 334965, 742714950, 10042408885191, 814556580116590856, 393147641272746246076745, 1123539400297807898234860367690, 18948227277012085227250633551784337179, 1881331163508674280605070386666674939623268684
Offset: 0

Views

Author

Paul D. Hanna, Oct 18 2009

Keywords

Comments

A002203 equals the logarithmic derivative of the Pell numbers (A000129).
Note that A002203(n^2) = (1+sqrt(2))^(n^2) + (1-sqrt(2))^(n^2).
Given g.f. A(x), (1-x)^(1/4) * A(x)^(1/8) is an integer series.

Examples

			G.f.: A(x) = 1 + 2*x + 19*x^2 + 964*x^3 + 334965*x^4 + 742714950*x^5 +...
log(A(x)) = 2*x + 34*x^2/2 + 2786*x^3/3 + 1331714*x^4/4 + 3710155682*x^5/5 + 60245508192802*x^6/6 + 5701755387019728962*x^7/7 +...+ A002203(n^2)*x^n/n +...
		

Crossrefs

Programs

  • PARI
    {a(n)=if(n==0,1,polcoeff(exp(sum(m=1,n,polcoeff(2*(1-x)/(1-2*x-x^2+x*O(x^(m^2))),m^2)*x^m/m)+x*O(x^(n^2))),n))}

Formula

Logarithmic derivative equals A165938.
Self-convolution of A166879.

A207835 G.f.: exp( Sum_{n>=1} 5*L(n)*x^n/n ), where L(n) = Fibonacci((n-1)^2) + Fibonacci((n+1)^2).

Original entry on oeis.org

1, 15, 200, 3525, 134355, 16781664, 6730280105, 7679335074975, 23795707614699850, 197148338964056588955, 4337960355881995023988299, 252594793852565664429620014530, 38838042059493582778244565420563025, 15744729667082405326504405819215652913325
Offset: 0

Views

Author

Paul D. Hanna, Feb 20 2012

Keywords

Comments

Given g.f. A(x), note that A(x)^(1/5) is not an integer series.
Compare the definition to the g.f. of the Fibonacci numbers:
1/(1-x-x^2) = exp( Sum_{n>=1} Lucas(n)*x^n/n ), where Lucas(n) = Fibonacci(n-1) + Fibonacci(n+1).

Examples

			G.f.: A(x) = 1 + 15*x + 200*x^2 + 3525*x^3 + 134355*x^4 + 16781664*x^5 +...
such that, by definition,
log(A(x))/5 = 3*x + 35*x^2/2 + 990*x^3/3 + 75059*x^4/4 + 14931339*x^5/5 + 7778817074*x^6/6 +...+ (Fibonacci((n-1)^2) + Fibonacci((n+1)^2))*x^n/n +...
		

Crossrefs

Programs

  • PARI
    {L(n)=fibonacci((n-1)^2)+fibonacci((n+1)^2)}
    {a(n)=polcoeff(exp(sum(m=1,n,5*L(m)*x^m/m)+x*O(x^n)),n)}
    for(n=0,21,print1(a(n),", "))

A166169 a(n) = Lucas(n^2) = A000204(n^2) for n >= 1.

Original entry on oeis.org

1, 7, 76, 2207, 167761, 33385282, 17393796001, 23725150497407, 84722519070079276, 792070839848372253127, 19386725908489881939795601, 1242282009792667284144565908482, 208406472252232726621841472637412401
Offset: 1

Views

Author

Paul D. Hanna, Oct 08 2009

Keywords

Crossrefs

Programs

  • Magma
    [ Lucas(n^2) : n in [1..50]]; // Vincenzo Librandi, Apr 14 2011
  • Mathematica
    Table[LucasL[n^2], {n, 1, 10}] (* G. C. Greubel, May 06 2016 *)
  • PARI
    a(n)=fibonacci(n^2-1)+fibonacci(n^2+1)
    

Formula

Logarithmic derivative of A166168.
a(n) = ((1 + sqrt(5))/2)^(n^2) + ((1 - sqrt(5))/2)^(n^2).
a(n) = Fibonacci(n^2 - 1) + Fibonacci(n^2 + 1).
Showing 1-4 of 4 results.