A372610 Decimal expansion of Sum_{k >= 1} floor((Pi/2)*k)/2^k.

2, 6, 6, 9, 2, 9, 1, 3, 3, 8, 5, 8, 2, 6, 7, 7, 1, 6, 5, 3, 5, 4, 3, 3, 0, 7, 0, 8, 6, 6, 1, 4, 1, 7, 3, 2, 2, 8, 3, 4, 6, 4, 5, 6, 6, 9, 2, 9, 1, 3, 3, 8, 5, 8, 2, 6, 7, 7, 1, 6, 5, 3, 5, 4, 3, 3, 0, 6, 9, 9, 3, 1, 5, 3, 8, 6, 0, 7, 7, 0, 0, 8, 0, 7, 2, 0, 9, 8, 9, 4

Offset: 1

Author

Paolo Xausa, May 07 2024

Keywords

• nonn
• cons

Examples

			2.669291338582677165354330708661417322834645669291338582677...
		

Links

• Paolo Xausa, Table of n, a(n) for n = 1..10000
• J. M. Borwein and P. B. Borwein, Strange Series and High Precision Fraud, The American Mathematical Monthly, Vol. 99, No. 7 (1992), pp. 622-640.

Crossrefs

Cf. A000796, A019669, A140758.

Programs

Mathematica

First[RealDigits[Sum[Floor[Pi*k/2]/2^k, {k, 400}], 10, 100]]

Formula

Approximately 339/127, correct to 67 digits: see Example 4.1 (a) in Borwein and Borwein (1992), p. 633.