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

Author

Jose Luis Garcia del Castillo, Jun 19 2014

Keywords

• nonn
• base

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.

Examples

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

Links

• Eric Weisstein's World of Mathematics, Feynman Point

Crossrefs

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

Extensions

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