Excel 2013 implements new spreadsheet functions, most for ODF / OpenFormula compatibility. See http://office.microsoft.com/en-us/excel-help/new-functions-in-excel-2013-HA103980604.aspx
Calc already knows most of them and "just" needs to import/export the known functions.
Working on this.
Eike Rathke committed a patch related to this issue.
It has been pushed to "master":
import/export new Excel 2013 ODF functions, fdo#60032
The patch should be included in the daily builds available at
http://dev-builds.libreoffice.org/daily/ in the next 24-48 hours. More
information about daily builds can be found at:
Affected users are encouraged to test the fix and report feedback.
Created attachment 73967 [details]
The following functions are handled, name specialities are given as
(in parentheses the en-US UI name) [in brackets the ODFF name]
BINOM.DIST.RANGE (B) [BINOM.DIST.RANGE]
FORMULATEXT (FORMULA) [FORMULA]
PDURATION (DURATION) [PDURATION]
UNICHAR(0) differs in that it does not generate an error in LibreOffice.
With implementation of bug 57180 also NUMBERVALUE is imported/exported.
With implementation of bug 60322 also SKEW.P (SKEWP) [SKEWP] is imported/exported.