A308259 a(n) is equal to the sum of the factorials of the digits of a(n-1), initial term is 3.

3, 6, 720, 5043, 151, 122, 5, 120, 4, 24, 26, 722, 5044, 169, 363601, 1454, 169, 363601, 1454, 169, 363601, 1454, 169, 363601, 1454, 169, 363601, 1454, 169, 363601, 1454, 169, 363601, 1454, 169, 363601, 1454, 169, 363601, 1454, 169, 363601, 1454, 169, 363601

Offset

1,1

Comments

From a(14) = 169, the sequence is stuck in the loop 363601, 1454, 169, 363601, 1454, ...

Links

Table of n, a(n) for n=1..45.

Shoei Takahashi, Unchone Lee, Hikaru Manabe, Aoi Murakami, Daisuke Minematsu, Kou Omori, and Ryohei Miyadera, Curious Properties of Iterative Sequences, arXiv:2308.06691 [math.GM], 2023.

Example

a(5) = 151, so a(6) = 1! + 5! + 1! = 1 + 120 + 1 = 122.

Mathematica

NestList[Total@ Map[Factorial, IntegerDigits[#]] &, 3, 36] (* Michael De Vlieger, Aug 21 2023 *)

Crossrefs

Cf. A061602, A306955.

Sequence in context: A157540 A179267 A171928 * A034879 A113588 A071106

Adjacent sequences: A308256 A308257 A308258 * A308260 A308261 A308262

Keyword

base,easy,nonn

Author

Romain Pinot, May 17 2019

Status

approved