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%I #39 Jul 13 2023 15:43:39
%S 13,29,39,47,56,66,96,99,120,139,156,166,209,224,232,235,242,288,299,
%T 301,306,320,343,351,405,407,412,429,439,452,458,463,468,475,478,486,
%U 506,538,540,544,548,556,559,560,567,569,575,577,584,591,609,621,622
%N Positions of the digit '7' in decimal expansion of Pi.
%C In the first 400 digits of Pi, 7 is rare and only appears 24 times. In the next 250 digits of Pi, 7 is common and appears 38 times. - _Bobby Jacobs_, Oct 18 2016
%H Amiram Eldar, <a href="/A036974/b036974.txt">Table of n, a(n) for n = 1..10000</a>
%H Bobby Jacobs, <a href="https://www.youtube.com/watch?v=3EDdjOxWE6I">Pirotechnics</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/PiDigits.html">Pi Digits</a>
%e 3.141592653589(7)932384626433832(7)950288419(7)1693993(7)510
%e 58209(7)494459230(7)81640628620899862803482534211(7)06(7)9
%e 8214808651328230664(7)093844609550582231(7)25359408128
%e 48111(7)450284102(7)0193852110555964462294895493038196
%e 44288109(7)56659334461284(7)5648233(7)86(7)831652(7)12019091
%e 4564856692346034861045432664821339360(7)2602491412(7)3
%e (7)2458(7)0066063155881(7)4881520920962829254091(7)1536436
%e (7)8925903600113305305488204665213841469519415116094
%e 3305(7)2(7)0365(7)5959195309218611(7)381932611(7)93105118548
%e 0(7)44623(7)9962(7)4956(7)351885(7)52(7)2489122(7)93818301194912
%e 98336(7)3362440656643086021394946395224(7)3(7)190(7)021(7)98
%e 60943(7)02(77)053921(7)1(7)62931(7)6(7)523846(7)481846(7)669405132
%e 00056812(7)14526356082(77)85(77)1342(7)5(77)896091(7)363(7)1(7)8(7)...
%t Flatten@Position[RealDigits[Pi - 3, 10, 500][[1]], 7] (* _Robert G. Wilson v_,Mar 07 2011 *)
%t Union[Flatten[SequencePosition[RealDigits[Pi,10,700][[1]],{7}]]]-1 (* _Harvey P. Dale_, Jul 13 2023 *)
%Y Cf. A000796.
%Y Cf. A037000, A037001, A037002, A037003, A037004, A037005, A037006, A037007, A037008.
%K base,nonn
%O 1,1
%A Nicolau C. Saldanha (nicolau(AT)mat.puc-rio.br)
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