3[47][0-9]{2}[ \-,]?[0-9]{6}[ \-,]?[0-9]{5}[ \-,]?
#+ number only field 34
344744720132669
377238242604156
#+ number string
<sometag1>somedata</sometag1><sometag2><num>344744720132669</num>
<sometag1>somedata</sometag1><sometag2><num>370000000000002</num>
#+ with spaces
<sometag1>somedata</sometag1><sometag2><num> 3447 447201 32669</num>
<sometag1>somedata</sometag1><sometag2><num> 3700 000000 00002</num>
#+ with dash
<sometag1>somedata</sometag1><sometag2><num>3447-447201-32669</num>
<sometag1>somedata</sometag1><sometag2><num>3700-000000-00002</num>
#+ with comma
<sometag1>somedata</sometag1><sometag2><num>3449,900969,59629</num>
<sometag1>somedata</sometag1><sometag2><num>3700,000000,00002</num>
#+ bigger numbers
<sometag1>somedata</sometag1><sometag2><num>3449900969593565566</num>
#+ bigger numbers with space
<sometag1>somedata</sometag1><sometag2><num>3449 900969 593565 566</num>
#- SHOULD NOT MATCH with other starting numbers
3549,900969,59356
<sometag1>somedata</sometag1><sometag2><num>5649 900969 593565 566</num>