Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #5 Apr 30 2019 16:41:36
%S 5,155,173,179,210,236,253,262,274,275,293,352,353,359,390,410,468,
%T 603,636,654,661,674,696,703,723,732,764,765,766,767,780,796,804,822,
%U 836,857,875,885,897,918,924,961,981,985,995,996,1015,1059,1200,1234,1246
%N Positions of balanced digits in the decimal expansion of Pi.
%C Cf. A108533 (strong digits), A108534 (weak digits). In the decimal expansion of Pi, balanced digits are much more rare than weak or strong ones.
%t re=RealDigits[N[Pi, 2900]][[1]];b={};Do[r=re[[n]];If[r==(re[[n-1]]+re[[n+1]])/2, b=Append[b, r]], {n, 2, 2899}];A108535=b
%t With[{pid=RealDigits[Pi,10,1300][[1]]},Flatten[Position[Partition[ pid,3,1],_?((#[[1]]+#[[3]])/2==#[[2]]&),1,Heads->False]]]+1 (* _Harvey P. Dale_, Apr 30 2019 *)
%Y Cf. A108533, A108534.
%K nonn,base
%O 1,1
%A _Zak Seidov_, Jun 08 2005