fHtmCoverCircleLatLon(ra,dec,radiusArcMin) returns a trixel table (a list) covering
the circle centered at that lat,lon, within that arc-minute radius.
A trixel table is a list of HtmIDStart,HtmIDEnd pairs that describe
the HTM triangles (all points of a triangle are between its HtmIDStart and HtmIDEnd.

public static IEnumerable fHtmCoverCircleLatLon(
	SqlDouble lat,
	SqlDouble lon,
	SqlDouble radiusArcMin
)

public:
static IEnumerable^ fHtmCoverCircleLatLon(
	SqlDouble lat, 
	SqlDouble lon, 
	SqlDouble radiusArcMin
)

static member fHtmCoverCircleLatLon : 
        lat:SqlDouble * 
        lon:SqlDouble * 
        radiusArcMin:SqlDouble -> IEnumerable 

create function fHtmCoverCircleLatLon(@lat float, @lon float, @radiusArcMin float) 
        returns bigint 
        as external name HTM.Sql.fHtmCoverCircleLatLon
select * from fHtmCoverCircLatLon(5,195,1)