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 1-2 of 2 results.

A068453 Factorial expansion of sqrt(e) = Sum_{n>=1} a(n)/n!.

Original entry on oeis.org

1, 1, 0, 3, 2, 5, 0, 4, 3, 9, 8, 2, 8, 0, 10, 15, 2, 10, 8, 19, 12, 4, 18, 23, 8, 4, 21, 15, 17, 1, 11, 19, 7, 25, 15, 3, 20, 5, 24, 25, 35, 9, 12, 25, 26, 22, 23, 11, 43, 46, 6, 0, 25, 27, 30, 6, 14, 20, 33, 5, 30, 23, 42, 4, 11, 19, 55, 63, 43, 12, 52, 51, 22, 29, 11, 8, 19, 35, 25
Offset: 1

Views

Author

Benoit Cloitre, Mar 10 2002

Keywords

Crossrefs

Cf. A067840 (e^2), A075874 (Pi).

Programs

  • Magma
    SetDefaultRealField(RealField(250)); [Floor(Sqrt(Exp(1)))] cat [Floor(Factorial(n)*Sqrt(Exp(1))) - n*Floor(Factorial((n-1))* Sqrt(Exp(1))) : n in [2..80]]; // G. C. Greubel, Nov 26 2018
    
  • Mathematica
    With[{b = Sqrt[E]}, Table[If[n == 1, Floor[b], Floor[n!*b] - n*Floor[(n - 1)!*b]], {n, 1, 100}]] (* G. C. Greubel, Nov 26 2018 *)
  • PARI
    vector(30,n,if(n>1,t=t%1*n,t=exp(.5))\1) \\ M. F. Hasler, Nov 25 2018
    
  • PARI
    default(realprecision, 250); b = sqrt(exp(1)); for(n=1, 80, print1(if(n==1, floor(b), floor(n!*b) - n*floor((n-1)!*b)), ", ")) \\ G. C. Greubel, Nov 26 2018
    
  • Sage
    def A068453(n):
        if (n==1): return floor(sqrt(e))
        else: return expand(floor(factorial(n)*sqrt(e)) - n*floor(factorial(n-1)*sqrt(e)))
    [A068453(n) for n in (1..80)] # G. C. Greubel, Nov 26 2018

Extensions

Name edited and keyword cons removed by M. F. Hasler, Nov 25 2018

A322506 Factorial expansion of 1/exp(2) = Sum_{n>=1} a(n)/n!.

Original entry on oeis.org

0, 0, 0, 3, 1, 1, 3, 0, 6, 4, 7, 5, 2, 9, 9, 8, 10, 8, 9, 1, 13, 18, 1, 2, 8, 15, 26, 10, 22, 1, 18, 9, 20, 10, 2, 6, 13, 19, 16, 38, 38, 3, 32, 5, 39, 24, 7, 27, 14, 41, 20, 39, 32, 7, 20, 35, 44, 50, 24, 34, 51, 14, 39, 47, 49, 15, 61, 54, 60, 52, 34, 60, 32, 72, 48, 12, 67, 52, 22, 48
Offset: 1

Views

Author

G. C. Greubel, Dec 12 2018

Keywords

Examples

			1/exp(2) = 0 + 0/2! + 0/3! + 3/4! + 1/5! + 1/6! + 3/7! + 0/8! + 6/9! +...
		

Crossrefs

Cf. A092553 (decimal expansion), 0 U A001204 (continued fraction).
Cf. A054977 (e), A067840 (e^2), A068453 (sqrt(e)), A237420 (1/e).

Programs

  • Magma
    SetDefaultRealField(RealField(250));  [Floor(Exp(-2))] cat [Floor(Factorial(n)*Exp(-2)) - n*Floor(Factorial((n-1))*Exp(-2)) : n in [2..80]];
    
  • Mathematica
    With[{b = 1/E^2}, Table[If[n == 1, Floor[b], Floor[n!*b] - n*Floor[(n - 1)!*b]], {n, 1, 100}]]
  • PARI
    default(realprecision, 250); b = exp(-2); for(n=1, 80, print1(if(n==1, floor(b), floor(n!*b) - n*floor((n-1)!*b)), ", "))
    
  • Sage
    b=exp(-2);
    def a(n):
        if (n==1): return floor(b)
        else: return expand(floor(factorial(n)*b) -n*floor(factorial(n-1)*b))
    [a(n) for n in (1..80)]
Showing 1-2 of 2 results.