A395992 - OEIS

%I #18 Jun 12 2026 08:43:13

%S 3,1,4,1,5,9,4,2,6,9,1,6,6,2,8,5,6,2,7,1,9,0,9,7,6,9,8,5,2,1,5,6,6,8,

%T 3,4,3,2,4,0,3,5,9,7,0,1,2,6,5,0,5,1,0,5,9,2,8,9,7,4,2,4,1,7,3,1,4,4,

%U 3,3,7,7,5,3,3,9,1,2,5,1,3,3,3,6,3,8,1,6,4,9,1,3,8,8,5,0,7,8,4,9

%N Decimal expansion of 20612/6561.

%C In 1851, Parker claimed erroneously that Pi, the ratio of a circle's circumference to its diameter, was not a transcendental number, but the ratio of whole numbers 20612 and 6561.

%C Has period 729 starting from a(2). - _Jianing Song_, Jun 12 2026

%H John A. Parker, <a href="https://archive.org/details/quadraturecircl00parkgoog/page/73/mode/1up">The Quadrature of the Circle</a>, (1851). See p. 73.

%H <a href="/index/Al#algebraic_01">Index entries for algebraic numbers, degree 1</a>.

%H <a href="/index/Rec#order_729">Index entries for linear recurrences with constant coefficients</a>, order 729.

%e 3.141594269166285627190976985215668343240359701...

%t RealDigits[20612/6561,10,100][[1]]

%Y Cf. A000796, A068079, A210622, A354617, A374829, A375820, A380152.

%K nonn,cons,easy

%O 1,1

%A _Stefano Spezia_, Jun 12 2026