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%I #18 Nov 10 2018 09:33:18
%S 1,3,3,5,1,1,1,1,1,2,1,2,2,2,4,4,5,2,1,2,4,1,5,4,1,2,3,1,4,3,1,4,1,3,
%T 1,4,2,4,2,1,1,8,1,2,1,1,6,1,1,3,1,2,4,3,2,3,7,3,3,1,1,6,4,4,2,3,1,3,
%U 1,1,1,1,3,1,4,1,1,2,9,6,2,1,1,2,1,1,1,1,2,2,3,1,4,1,1,2,1,4,3,1,1,3,1,2,1,3,4,3,2,4,2,3,2,6,5,1,1,1,3,1,4,1,1,4,1,2,8,3,1,2,1,1,2,1,1,1,2,1,1,1,1,3,2,2,4,1,3,1,2,1,3,1,1,1,3,1,2,3,1,1,2,3,5,1,4,1,2,1,3,1,7,2,2,1,5,2,3,1,2,1,2,1,1,1,1,3
%N Differences between positions of 1's in binary expansion of Pi.
%F a(n) = A004711(n+1) - A004711(n) (A004711 is concerned with Pi/4, but they are essentially the same).
%t Differences@ Position[RealDigits[Pi, 2, 250][[1]], 1][[All, 1]] (* _Michael De Vlieger_, Oct 20 2018 *)
%Y Cf. A004711, A320299.
%K nonn,base
%O 1,2
%A _Jack Zhang_, Oct 10 2018