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A270097 Discriminator sequence for the powers of 2:  smallest positive integer d such that 2^0, 2^1, ..., 2^{n-1} are all incongruent modulo d. 1
1, 2, 4, 5, 9, 9, 11, 11, 11, 11, 13, 13, 19, 19, 19, 19, 19, 19, 25, 25, 29, 29, 29, 29, 29, 29, 29, 29, 37, 37, 37, 37, 37, 37, 37, 37, 53, 53, 53, 53, 53, 53, 53, 53, 53, 53, 53, 53, 53, 53, 53, 53, 59, 59, 59, 59, 59, 59, 61, 61, 67, 67, 67, 67, 67, 67, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 101 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

The discriminator of a finite sequence s is the smallest positive integer d such that all the elements of s are incongruent modulo d.  The sequence in question is the discriminator of the first n powers of 2.

LINKS

Table of n, a(n) for n=0..82.

Zhi-Wei Sun, On functions taking only prime values, J. Number Theory 133(2013), no.8, 2794-2812.

CROSSREFS

Sequence in context: A116920 A116919 A270429 * A167511 A242398 A174112

Adjacent sequences:  A270094 A270095 A270096 * A270098 A270099 A270100

KEYWORD

nonn

AUTHOR

Jeffrey Shallit, Mar 11 2016

STATUS

approved

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Last modified June 17 17:43 EDT 2021. Contains 345085 sequences. (Running on oeis4.)