2,1

7*Pi is also the surface area of a sphere whose diameter equals the square root of 7. 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

Table of n, a(n) for n=2..105.

21.99114857512855266923850368295652018938...

RealDigits[7*Pi, 10, 120][[1]] (* Harvey P. Dale, Jan 14 2015 *)

Cf. A000796, A019692, A122952, A019694, A019669, A228719 (Pi through 6*Pi).

Sequence in context: A198106 A243261 A230358 * A108290 A308804 A108291

Adjacent sequences: A228718 A228719 A228720 * A228722 A228723 A228724

nonn,cons

Omar E. Pol, Oct 03 2013

approved