A336752 The 'Look and Say' sequence of the concatenation of the prime numbers A033308.

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

Offset

1,2

Comments

Concatenate all the decimal prime numbers, see A033308, then describe the resulting infinite string using the 'Look and Say' method of A005150.

Links

Table of n, a(n) for n=1..100.

J. H. Conway and Brady Haran, Look-and-Say Numbers (2014), Numberphile video.

Wikipedia, Look-and-say sequence.

Example

The concatenation of the primes starts "23571113171923293137...".
a(1) = 1, a(2) = 2 as there is one '2' at the start of the string.
a(9) = 3, a(10) = 1 as the primes '11' and '13' from the substring '1113'. which starts with three 1's.

Crossrefs

Cf. A033308, A005150, A001155, A056815, A000040.

Sequence in context: A101809 A127203 A227288 * A126132 A129982 A052552

Adjacent sequences: A336749 A336750 A336751 * A336753 A336754 A336755

Keyword

nonn,base

Author

Scott R. Shannon, Aug 15 2020

Status

approved