A372925 Decimal expansion of Sum_{k >= 1} A210436(k)^2/2^k.

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

Offset

1,1

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.

Formula

Approximately 196669/37303, correct to 88 digits: see Example 4.2 (c) in Borwein and Borwein (1992), pp. 634-635, although there is a typo in the denominator of the summands (6^k instead of 2^k).

Example

5.2722033080449293622496850119293354421896362222877516553628...

Mathematica

First[RealDigits[Sum[IntegerLength[6^k]^2/2^k, {k, 350}], 10, 100]]

Crossrefs

Cf. A000079, A000400, A210436, A372804.

Sequence in context: A344760 A343422 A214969 * A093591 A132800 A348432

Adjacent sequences: A372922 A372923 A372924 * A372926 A372927 A372928

Keyword

nonn,cons

Author

Paolo Xausa, May 17 2024

Status

approved