OFFSET
1,3
EXAMPLE
a(6) = 1! + 5! = 121 because 1 and 5 are the positive integers that are <= 6 and are relatively prime to 6.
MATHEMATICA
Table[Total[Select[Range[n], CoprimeQ[#, n]&]!], {n, 30}] (* Harvey P. Dale, Apr 07 2022 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Leroy Quet, Nov 05 2000
STATUS
approved