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

Author

Scott R. Shannon, Dec 23 2024

Keywords

• nonn
• base

Examples

			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.
		

Links

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

Crossrefs

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

Programs

Mathematica

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