A379453 Numbers that decrease when they are replaced by the "Look and Say" description (cf. A045918) of their prime factors, counted with multiplicity.

49, 64, 81, 125, 128, 243, 256, 289, 343, 361, 512, 529, 625, 729, 841, 961, 1024, 1250, 1331, 1369, 1458, 1681, 1715, 1849, 1875, 2048, 2187, 2197, 2209, 2401, 2500, 2809, 2916, 3087, 3125, 3375, 3481, 3721, 4096, 4374, 4489, 4802, 4913, 5000, 5041, 5329, 5488, 5625, 5832, 6075, 6125, 6241, 6250, 6561, 6859, 6889, 7203, 7776, 7921, 8000, 8192, 8575, 8748

Offset

1,1

Links

Scott R. Shannon, Table of n, a(n) for n = 1..5000

Example

49 is a term as 49 = 7^2 which becomes 27 when replaced by the "Look and Say" description of its prime factors, and 27 is smaller than 49.

Mathematica

Select[Range[8750], #>FromDigits[Flatten[IntegerDigits/@Reverse/@FactorInteger[#]]]&] (* James C. McMahon, Dec 23 2024 *)

Crossrefs

Cf. A045918, A379454, A379455, A005150, A367974, A369132, A369092.

Sequence in context: A374937 A065807 A038678 * A225120 A308250 A215056

Adjacent sequences: A379450 A379451 A379452 * A379454 A379455 A379456

Keyword

nonn,base

Author

Scott R. Shannon, Dec 23 2024

Status

approved