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%I #17 May 23 2021 15:37:37
%S 2,3,0,6,0,1,9,3,7,4,8,1,8,7,0,7,2,1,2,5,7,3,8,4,1,0,3,4,5,8,5,2,8,2,
%T 9,6,9,3,8,5,2,4,5,5,3,6,2,5,2,7,8,2,9,6,1,6,8,0,9,7,1,0,5,4,2,7,2,4,
%U 7,4,9,6,9,2,3,1,5,8,1,4,8,4,0,7,1,9,8,2,1,9,1,8,9
%N Decimal expansion of 2*(1+5*sqrt(2))/7.
%C Dissect the unit square into 7 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 = 7.
%e 2.3060193748187072125738410...
%t RealDigits[2 (1 + 5 Sqrt[2])/7, 10, 200][[1]] // Flatten
%Y Similar sequences into k regions: A344520 (k=3), A344554 (k=5), A344568 (k=9), A344569 (k=17).
%K nonn,cons
%O 1,1
%A _Wesley Ivan Hurt_, May 23 2021