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.

A229939 Decimal expansion of 9*Pi/10.

Original entry on oeis.org

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

Views

Author

Omar E. Pol, Oct 06 2013

Keywords

Comments

With offset 2, decimal expansion of 9*Pi.
9*Pi is also the surface area of a sphere whose diameter equals the square root of 9. More generally x*Pi is also the surface area of a sphere whose diameter equals the square root of x. - Omar E. Pol, Dec 22 2013

Examples

			9*Pi/10 = 2.827433388230813914616379044951552595777...
9*Pi = 28.27433388230813914616379044951552595777...
		

Crossrefs

Programs

Formula

9*Pi = Sum_{j >= 0} j*(j - 1)*(j - 2)*(j - 3)*2^(j+1) / ((2*j + 1)*binomial(2*j, j)). - Peter Bala, Nov 21 2023