Vajra

The eldest brother of the Pandavas, filled with sorrow, addressed Subhadra, saying,

1. This son of thy son will be the king of the Kurus.The survivor of the Yadus, Vajra, has been made a king. 
2. Parikshit will rule in Hastinapura, while the Yadava prince, Vajra, will rule in Shakraprastha. 

He should be protected by thee. Never set thy heart on unrighteousness.’

Source
http://www.sacred-texts.com/hin/m17/m17001.htm

Wiki
http://en.wikipedia.org/wiki/Vajra_(King_Aniruddha's_Son)

Genalogy
http://www.jatland.com/home/Vajra

Yadav
http://iyadav.com/krishna-great-grandson-vajra/

Shandilya
http://holydham.com/shandilya-muni-describes-vrajabhumi-to-vajranabh/

Vrindavan - 16

http://tourvrindavan.blogspot.com/search/label/Vajranabha

Rajastan - 4 of 16 now

http://theonlymale.blogspot.com/search/label/Vajra

Orissa - 1 of 16 now

http://threeinformation.blogspot.com/search/label/Sakshi

Dwarka (Before going to mathura)

Vajranabh, Lord Krishna's successor and great grandson, is believed to have built the present temple Dwarkanath, also called Trilok Sundar. Many Hindus fervently believe that the temple was erected in one night by a supernatural agency, under Vajranabh's direction.

http://divineentrance.blogspot.com/