Shiva Purana

siva.sh/siva-purana/vishweshwara-samhita/25/34

शिखायामेकरुद्रा क्षं शिरसा त्रिंशतं वहेत् । पंचाशच्च गले दध्याद्बाह्वोः षोडश षोडश ३४ ।

sanskrit

One Rudrākṣa should be worn on the śikhā (tuft of hair), thirty on the head, fifty on the neck, and sixteen each on both arms.

english translation

zikhAyAmekarudrA kSaM zirasA triMzataM vahet | paMcAzacca gale dadhyAdbAhvoH SoDaza SoDaza 34 |

hk transliteration by Sanscript