Narada Purana (Jyotisha Selections) · by Vyasa
Chapter 6 · Calendar, Muhurta Elements
कालमानं मुहूर्ताङ्गानि च
चंडीशचंडायुधाख्यस्तस्मिन्नैवाचरेच्छुभम् ।त्रयोदश स्युर्मिलनसंख्यया तिथिवारयोः ॥ २३५ ॥
In the full Narada Purana (Purva Bhaga) this is chapter 56, verse 235.
Its name is Chandisha-Chandayudha. Never do a good act in it. Now say the numbers of the tithi (moon day) and the weekday add up to thirteen.
Simple meaning: This bad combination is called Chandisha-Chandayudha. Do no good act in it.
क्रकचो नाम योगोऽयं मंगलेष्वतिगर्हितः ।
Tithi plus weekday making 13 is Krakacha, very bad. Sunday on the 7th or Wednesday on the 1st opens another.
संवतयोगो विज्ञेयः शुभकर्मविनाशकृत् ।
Those two pairs make Samvata, which can spoil good acts. The list of 28 day mixes begins with Ananda.
ध्वांक्षध्वजाख्यश्रीवत्सवज्रमुद्गरछत्रकाः ।
The list of day mixes goes on with twelve more names.