OFFSET
0,2
EXAMPLE
a(16)=16721 because 1!+6! = 721.
MATHEMATICA
Table[FromDigits[Join[IntegerDigits[n], IntegerDigits[Total[IntegerDigits[n]!]]]], {n, 0, 40}] (* Harvey P. Dale, Jul 13 2023 *)
CROSSREFS
KEYWORD
base,easy,nonn
AUTHOR
Jason Earls, Jun 16 2005
STATUS
approved