A349403 - OEIS

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A349403

Sum of the digits of Sum_{k=1..n} k!.

1

0, 1, 3, 9, 6, 9, 18, 18, 18, 18, 27, 36, 36, 54, 54, 36, 45, 45, 72, 72, 63, 81, 99, 99, 117, 108, 99, 126, 126, 144, 117, 162, 144, 153, 171, 171, 153, 180, 180, 198, 171, 225, 207, 252, 225, 261, 261, 252, 270, 234, 270, 261, 279, 324, 324, 306, 342, 333, 333, 297, 351, 360, 351, 333, 387, 405, 369

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,3

COMMENTS

If n > 4, then 9 divides a(n).

LINKS

Table of n, a(n) for n=0..66.

FORMULA

a(n) = A007953(A007489(n)).

a(n) = A127554(n+1) - 1 for n > 3.

EXAMPLE

n | A007489 | A003422 | a(n) | A127554 |

-----+----------+---------+------+---------+

0 | 0 | 0 | 0 | 0 |

1 | 1 | 1 | 1 | 1 |

2 | 3 | 2 | 3 | 2 |

3 | 9 | 4 | 9 | 4 |

4 | 33 | 10 | 6 | 1 |

5 | 153 | 34 | 9 | 7 |

6 | 873 | 154 | 18 | 10 |

7 | 5913 | 874 | 18 | 19 |

8 | 46233 | 5914 | 18 | 19 |

9 | 409113 | 46234 | 18 | 19 |

10 | 4037913 | 409114 | 27 | 19 |

11 | 43954713 | 4037914 | 36 | 28 |

MATHEMATICA

Table[Total[IntegerDigits[Sum[k!, {k, n}]]], {n, 0, 66}] (* Stefano Spezia, Nov 16 2021 *)

PROG

(PARI) a(n) = sumdigits(sum(k=1, n, k!));

CROSSREFS

Cf. A004152, A007489, A007953, A127554.

Sequence in context: A343864 A309613 A189272 * A131954 A154593 A283439

Adjacent sequences: A349400 A349401 A349402 * A349404 A349405 A349406

KEYWORD

nonn,base

AUTHOR

Seiichi Manyama, Nov 15 2021

STATUS

approved