Sylvester's Sequence - Closed Form Formula and Asymptotics

Closed Form Formula and Asymptotics

The Sylvester numbers grow doubly exponentially as a function of n. Specifically, it can be shown that

for a number E that is approximately 1.264084735305302. This formula has the effect of the following algorithm:

s0 is the nearest integer to E2; s1 is the nearest integer to E4; s2 is the nearest integer to E8; for sn, take E2, square it n more times, and take the nearest integer.

This would only be a practical algorithm if we had a better way of calculating E to the requisite number of places than calculating sn and taking its repeated square root.

The double-exponential growth of the Sylvester sequence is unsurprising if one compares it to the sequence of Fermat numbers Fn; the Fermat numbers are usually defined by a doubly exponential formula, but they can also be defined by a product formula very similar to that defining Sylvester's sequence:

Read more about this topic:  Sylvester's Sequence

Famous quotes containing the words closed, form and/or formula:

    Night hath closed all in her cloak,
    Twinkling stars love-thoughts provoke,
    Danger hence good care doth keep,
    Jealousy itself doth sleep;
    Sir Philip Sidney (1554–1586)

    It is absolutely impossible to transcend the laws of nature. What can change in historically different circumstances is only the form in which these laws expose themselves.
    Karl Marx (1818–1883)

    Given for one instant an intelligence which could comprehend all the forces by which nature is animated and the respective positions of the beings which compose it, if moreover this intelligence were vast enough to submit these data to analysis, it would embrace in the same formula both the movements of the largest bodies in the universe and those of the lightest atom; to it nothing would be uncertain, and the future as the past would be present to its eyes.
    Pierre Simon De Laplace (1749–1827)