A372804 Decimal expansion of Sum_{k >= 1, A034887(k) even} 1/2^k.

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

Offset: 0

Author

Paolo Xausa, May 13 2024

Keywords

• nonn
• cons

Examples

			0.1112195121951219512195121951220497309227983312303343426891...
		

Links

• Paolo Xausa, Table of n, a(n) for n = 0..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. A000079, A034887.

Programs

Mathematica

First[RealDigits[Sum[If[OddQ[IntegerLength[2^k]], 0, 1/2^k], {k, 350}], 10, 100]]

Formula

Approximately 114/1025, correct to 30 digits: see Example 4.2 (b) in Borwein and Borwein (1992), p. 634.