A379454 -id:A379454 - cp's OEIS frontend

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

Scott R. Shannon, Dec 23 2024

			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.

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

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

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

A379455 Numbers that decrease two times in succession when they are iteratively replaced by the "Look and Say" description (cf. A045918) of their prime factors, counted with multiplicity.

Original entry on oeis.org

1849, 7921, 38809, 79507, 146529, 160801, 200978, 226981, 327697, 654481, 1113032, 1653125, 1731619, 1765376, 2109375, 2588881, 3418927, 3857868, 4182703, 5640625, 6492304, 6553600, 6892100, 7103125, 7845601, 8438707, 9509327, 11039981, 11880448, 12068352, 12106067, 12584111, 13227109, 14895500, 16843208, 17149469, 17372224, 18081075, 18852697, 19523584

Offset: 1

Scott R. Shannon, Dec 23 2024

nonn

			1849 is a term as 1849 = 43^2 which becomes 243 when replaced by the "Look and Say" description of its prime factors, and 243 is smaller than 1849, and 243 = 3^5 which becomes 53 when replaced by the "Look and Say" description of its prime factors, and 53 is smaller than 243.

Scott R. Shannon, Table of n, a(n) for n = 1..568

Cf. A045918, A379453, A379454, A005150, A367974, A369132, A369092.

cp's OEIS Frontend

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

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