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Decimal expansion of 2*(1+sqrt(26))/5.
4

%I #22 May 23 2021 15:37:48

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

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

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

%N Decimal expansion of 2*(1+sqrt(26))/5.

%C Dissect the unit square into 5 regions with equal areas from a given midpoint on the squares edge. This sequence gives the decimal expansion of the perimeter of the triangular region with unit height.

%F Decimal expansion of 2*(1 + k*sqrt(1/k^2 + 1))/k, where k = 5.

%e 2.43960780543711393201128964360...

%t RealDigits[2 (1 + Sqrt[26])/5, 10, 200][[1]] // Flatten

%Y Similar sequences into k regions: A344520 (k=3), A343069 (k=7), A344568 (k=9), A344569 (k=17).

%K nonn,cons

%O 1,1

%A _Wesley Ivan Hurt_, May 23 2021