A243955 a(n) is the starting position of the first occurrence of a string of n 9's in the decimal expansion of 2*Pi.

12, 79, 761, 761, 761, 761, 761, 36356642, 1068822186

Offset

1,1

Comments

This sequence denotes the position of the Feynman point in the digits of tau = 2*Pi, from a(3) to a(7). Note how compared with A048940, tau has a Feynman point one digit longer, and one position lower, because at this point, the decimal expansion of Pi is 499999987, giving 99999997 when multiplied by 2.

Links

Table of n, a(n) for n=1..9.

Eric Weisstein's World of Mathematics, Feynman Point

Example

The position of one consecutive 9 in 2*Pi=6.283185307179 is on the 12th decimal digit.

Crossrefs

Cf. A048940 (similar, with Pi), A019692 (decimal expansion of 2*Pi).

Sequence in context: A035042 A061593 A344728 * A232044 A190216 A160559

Adjacent sequences: A243952 A243953 A243954 * A243956 A243957 A243958

Keyword

nonn,base

Author

Jose Luis Garcia del Castillo, Jun 19 2014

Extensions

a(9) from Chai Wah Wu, Sep 30 2019

Status

approved