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%I #21 Aug 21 2023 13:59:05
%S 3,6,720,5043,151,122,5,120,4,24,26,722,5044,169,363601,1454,169,
%T 363601,1454,169,363601,1454,169,363601,1454,169,363601,1454,169,
%U 363601,1454,169,363601,1454,169,363601,1454,169,363601,1454,169,363601,1454,169,363601
%N a(n) is equal to the sum of the factorials of the digits of a(n-1), initial term is 3.
%C From a(14) = 169, the sequence is stuck in the loop 363601, 1454, 169, 363601, 1454, ...
%H Shoei Takahashi, Unchone Lee, Hikaru Manabe, Aoi Murakami, Daisuke Minematsu, Kou Omori, and Ryohei Miyadera, <a href="https://arxiv.org/abs/2308.06691">Curious Properties of Iterative Sequences</a>, arXiv:2308.06691 [math.GM], 2023.
%e a(5) = 151, so a(6) = 1! + 5! + 1! = 1 + 120 + 1 = 122.
%t NestList[Total@ Map[Factorial, IntegerDigits[#]] &, 3, 36] (* _Michael De Vlieger_, Aug 21 2023 *)
%Y Cf. A061602, A306955.
%K base,easy,nonn
%O 1,1
%A _Romain Pinot_, May 17 2019