A036974 Positions of the digit '7' in decimal expansion of Pi.

13, 29, 39, 47, 56, 66, 96, 99, 120, 139, 156, 166, 209, 224, 232, 235, 242, 288, 299, 301, 306, 320, 343, 351, 405, 407, 412, 429, 439, 452, 458, 463, 468, 475, 478, 486, 506, 538, 540, 544, 548, 556, 559, 560, 567, 569, 575, 577, 584, 591, 609, 621, 622

Offset: 1

Author

Nicolau C. Saldanha (nicolau(AT)mat.puc-rio.br)

Keywords

• base
• nonn

Comments

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

Examples

			3.141592653589(7)932384626433832(7)950288419(7)1693993(7)510
58209(7)494459230(7)81640628620899862803482534211(7)06(7)9
8214808651328230664(7)093844609550582231(7)25359408128
48111(7)450284102(7)0193852110555964462294895493038196
44288109(7)56659334461284(7)5648233(7)86(7)831652(7)12019091
4564856692346034861045432664821339360(7)2602491412(7)3
(7)2458(7)0066063155881(7)4881520920962829254091(7)1536436
(7)8925903600113305305488204665213841469519415116094
3305(7)2(7)0365(7)5959195309218611(7)381932611(7)93105118548
0(7)44623(7)9962(7)4956(7)351885(7)52(7)2489122(7)93818301194912
98336(7)3362440656643086021394946395224(7)3(7)190(7)021(7)98
60943(7)02(77)053921(7)1(7)62931(7)6(7)523846(7)481846(7)669405132
00056812(7)14526356082(77)85(77)1342(7)5(77)896091(7)363(7)1(7)8(7)...
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000
• Bobby Jacobs, Pirotechnics
• Eric Weisstein's World of Mathematics, Pi Digits

Crossrefs

Cf. A000796.

Cf. A037000, A037001, A037002, A037003, A037004, A037005, A037006, A037007, A037008.

Programs

Mathematica

Flatten@Position[RealDigits[Pi - 3, 10, 500][[1]], 7] (* Robert G. Wilson v,Mar 07 2011 *)
Union[Flatten[SequencePosition[RealDigits[Pi,10,700][[1]],{7}]]]-1 (* Harvey P. Dale, Jul 13 2023 *)