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.

A207651 G.f.: Sum_{n>=0} Product_{k=1..n} (1 - (1-x)^k)/(1 - x^k).

Original entry on oeis.org

1, 1, 3, 8, 25, 83, 323, 1410, 7062, 39660, 248287, 1709505, 12843315, 104446836, 913968191, 8560027375, 85427505885, 904899664970, 10139054456975, 119802780498730, 1488769376468607, 19409525611304801, 264890181139521141, 3776619220990535910
Offset: 0

Views

Author

Paul D. Hanna, Feb 19 2012

Keywords

Examples

			G.f.: A(x) = 1 + x + 3*x^2 + 8*x^3 + 25*x^4 + 83*x^5 + 323*x^6 +...
such that, by definition,
A(x) = 1 + (1-(1-x))/(1-x) + (1-(1-x))*(1-(1-x)^2)/((1-x)*(1-x^2)) + (1-(1-x))*(1-(1-x)^2)*(1-(1-x)^3)/((1-x)*(1-x^2)*(1-x^3)) +...
		

Crossrefs

Programs

  • PARI
    {a(n)=polcoeff(sum(m=0,n,prod(k=1,m,(1-(1-x)^k)/(1-x^k +x*O(x^n)) )),n)}
    for(n=0,25,print1(a(n),", "))

Formula

a(n) ~ 2*exp(Pi^2/12) * 6^(n+3/2) * n^(n+1) / (exp(n) * Pi^(2*n+2)). - Vaclav Kotesovec, Oct 31 2014

A207652 G.f.: Sum_{n>=0} Product_{k=1..n} ((1+x)^k - 1)/(1 - x^k).

Original entry on oeis.org

1, 1, 3, 10, 45, 249, 1709, 13912, 131168, 1402706, 16757321, 221018769, 3188425939, 49925523804, 843121969923, 15272776193787, 295372123082865, 6073931908657770, 132329525329523223, 3044691799670213778, 73771773281455834427, 1877511491197391256001
Offset: 0

Views

Author

Paul D. Hanna, Feb 19 2012

Keywords

Examples

			G.f.: A(x) = 1 + x + 3*x^2 + 10*x^3 + 45*x^4 + 249*x^5 + 1709*x^6 +...
such that, by definition,
A(x) = 1 + ((1+x)-1)/(1-x) + ((1+x)-1)*((1+x)^2-1)/((1-x)*(1-x^2)) + ((1+x)-1)*((1+x)^2-1)*((1+x)^3-1)/((1-x)*(1-x^2)*(1-x^3)) +...
		

Crossrefs

Programs

  • PARI
    {a(n)=polcoeff(sum(m=0,n,prod(k=1,m,((1+x)^k-1)/(1-x^k +x*O(x^n)) )),n)}
    for(n=0,40,print1(a(n),", "))

Formula

From Vaclav Kotesovec, Oct 31 2014: (Start)
a(n) ~ 6*sqrt(2) * 12^n * n! / (exp(Pi^2/24) * Pi^(2*n+2)).
a(n) ~ 12^(n+1) * n^(n+1/2) / (exp(n + Pi^2/24) * Pi^(2*n+3/2)).
(End)

A207653 G.f.: Sum_{n>=0} Product_{k=1..n} (1 - (1-x)^(2*k-1))/(1 - x^(2*k-1)).

Original entry on oeis.org

1, 1, 4, 16, 77, 460, 3287, 27561, 265307, 2880875, 34821316, 463543454, 6737545832, 106158368798, 1802204594518, 32793160634292, 636683459975767, 13137118248246982, 287070448575006268, 6622644707103106925, 160846900060253917905, 4102379491083664461080
Offset: 0

Views

Author

Paul D. Hanna, Feb 19 2012

Keywords

Examples

			G.f.: A(x) = 1 + x + 4*x^2 + 16*x^3 + 77*x^4 + 460*x^5 + 3287*x^6 +...
such that, by definition,
A(x) = 1 + (1-(1-x))/(1-x) + (1-(1-x))*(1-(1-x)^3)/((1-x)*(1-x^3)) + (1-(1-x))*(1-(1-x)^3)*(1-(1-x)^5)/((1-x)*(1-x^3)*(1-x^5)) +...
		

Crossrefs

Programs

  • PARI
    {a(n)=polcoeff(sum(m=0,n,prod(k=1,m,(1-(1-x)^(2*k-1))/(1-x^(2*k-1) +x*O(x^n)) )),n)}
    for(n=0,40,print1(a(n),", "))

Formula

From Vaclav Kotesovec, Oct 31 2014: (Start)
a(n) ~ 6*sqrt(2) * exp(Pi^2/24) * 12^n * n! / Pi^(2*n+2).
a(n) ~ exp(Pi^2/24) * 12^(n+1) * n^(n+1/2) / (exp(n) * Pi^(2*n+3/2)).
(End)
Showing 1-3 of 3 results.