A229939 - OEIS

A229939

Decimal expansion of 9*Pi/10.

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

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OFFSET

1,1

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

LINKS

Table of n, a(n) for n=1..104.

Index entries for transcendental numbers

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

EXAMPLE

9*Pi/10 = 2.827433388230813914616379044951552595777...

9*Pi = 28.27433388230813914616379044951552595777...

MATHEMATICA

First[RealDigits[9*Pi, 10, 100]] (* Paolo Xausa, Jun 18 2024 *)

PROG

(PARI) .9*Pi \\ Charles R Greathouse IV, Oct 01 2022